DE2620513C2 - Seismic data processing device - Google Patents

Description

31. Device according to claim 28, characterized in that

- the control channel (4091, Fig. 48) has delay soundings (4078) and triple pairs of conductors (Du D ₂ , Dj, Fig. 6), and that

- Each transmitter-receiver circuit comprises a majority selection circuit (U1, Fi g. 6), via which control signals can be selected via two of the three conductor pairs / ugeführc and a false cranzcigeschaltung (130, Fig. 6) can be connected, which interrupts the connection on a indicating three pairs of conductors (Fig. 6).

The invention relates to a mixed data processing device according to the preamble of claim 1, emitted by a sound or pressure source and reflected seismic signals captured, digitized and time-division multiplexed to a central station further processing and evaluation transfers.

In seismic exploration, an acoustic wave signal is generated at or near the surface of the earth generated. The acoustic wave travels downwards and is reflected by underground layers, from where the wave returns to the surface of the earth. The reflected seismic waves are sensitive by seismic sensors displayed in a linear grouping or row on or in distributed near the surface of the earth.

In current practice, 25 to 30 are seismic Detectors, often referred to as sensors, equidistantly along a single section of cable distributed, which can have a length of 30 to 100 m. The sensors are all electrical to one another connected to form a single elongated data channel. 50 or more such cable sections, each of which represents a channel for signal transmission; are together to form a cable arrangement coupled from 3000 m or more. The output of each or several channels is with one central signal processing device connected, which is provided at one end of the cable assembly. A separate pair of wires is required for each channel. There must therefore be 50 or more such pairs of Lines are available. Because of the cost and weight of such a large number of leads arrangements have been proposed in which the output signals from each channel are time division multiplexed through a single data transmission channel.

The invention is discussed below in connection with geophysical exploration, but it can can also be used to display objects that are underwater, e.g. B. big fish, Schools of fish, ships or the like.

Known similar prior art devices are shown, for example, in US patents 36 52 979, 37 48 638, 38 51 302 and 38 73 961. All of these aforementioned patents relate to on seismic measuring equipment in which a signal processing device receives the seismic data of a Sensor or a seismic sensor group digitally represents. By using different multiplex methods the data are transmitted to a recording device via a telemetry channel. as DE-OS is an example of a known device for multiplex transmission of seismic signals 24 33 191 briefly considered. This is also the case with this seismic one, which is the starting point for the invention ! 5 measuring device will be a variety of in mutual Distance from one another arranged one behind the other transmitter-receiver units used, each one have a single input channel for receiving measuring signals. Depending on a first, from a central station according to the number of transmitter-receiver units transmitted sequence of control pulses the receiver assemblies take scanning signals from the assigned geophones or hydrophones which are then initially locally, i. H. in the relevant transmitter-receiver unit. Then the stored data are processed step by step according to a further sequence of control impulses Step, d. H. pushed from one to the next transmitter / receiver unit and stored in between chert. After each shifting step, the stored data sample is regenerated and again cached. The known arrangement corresponds in principle to a shift register in which a full Processing time is required to transfer all data from the individual local transceiver units to the Central station to transmit.

As mentioned above, a seismic sensor array is an array from 30 to in length 100 m. An acoustic wave whose wave front runs roughly parallel to the plane in which the seismic Sensors are arranged, arrives at all sensors approximately at the same time, whereby the output signal through Summation is amplified. Under actual seismic prospecting conditions, this ideal case rarely occurs, except in such a case where the wavefront is vertical from a reflective, subterranean Interface, which is directly below the sensor arrangement, is reflected. In the more common one In this case, the acoustic wavefront runs in a Winso kcl, i.e. at an angle to the sensor arrangement. This hits the Weiienfront at one end of the arrangement earlier than at the other end. The propagation time of the wavefront About the arrangement depends on the phase velocity of the seismic wave, the wavelength the acoustic wave, the length of the arrangement and the depth of the reflective interface, but also also on other factors. If the length of the arrangement is great compared to the wavelength of the is acoustic wave, the arrangement attenuates the acoustic wave. Therefore the seismic sensor arrangement should be shorter than the wavelength of the incident seismic waves to avoid attenuation, and preferably the array should be shorter than a quarter of this wavelength in order to provide good response obtain.

So far the energy has been at the lower end of the seismic spectrum, with wavelengths in the hundreds Meters of interest. Use quite a long time

Arrangements were found to be satisfactory. In more recently, however, a greater resolution of geological stratifications, e.g. B. when exploring underground Structures required. A higher resolution requires the use and thus display seismic Waves of higher frequencies. The wavelengths of energy at the top of the seismic spectrum however, are comparable to the length (and often much shorter than the length) of conventional seismic systems Sensor assemblies that are in operation today. It is therefore desirable to have a long seismic To replace the sensor arrangement in each cable section with many shorter seismic sensor arrangements. One however, such a solution to this problem has so far been made in view of the difficulties in data processing and the great number of ladders that would be required have been considered impossible because of doing so extremely expensive cable assemblies would be required, the size and mass of which are practical Standpoint would no longer be viable.

There is therefore a need for seismic data processing equipment, compared to devices known today, an increase in resolution of extensive seismic facilities without affecting the weight or mass of the seismic cable arrangement is increased.

The invention is therefore based on the object of a To create seismic data processing equipment, which is characterized by a much greater resolution the acquisition and evaluation of seismic data, so that a much better distinction different geological layers down to relatively great depths is possible.

The solution to this problem according to the invention is specified in claim 1.

Advantageous further developments of the inventive concept are characterized in the subclaims.

According to the invention, in seismic data processing devices with a variety of elementary seismic sensor units, the electronic Sender-receiver units are assigned, soft during operation seismic data signals from the sensor units via a transmission link in transmit a seismic cable to a common central station using multiplex technology, proposed an additional multiplex device in each transceiver unit for sequential interrogation of the output from each of the elementary seismic sensor units of a certain set of associated sensor units as well an electronic circuit in each transmitter-receiver unit for connecting the outputs of the respective Transceiver unit to be provided on the transmission link so that during operation the outputs from each of the seismic sensor units of the respective set through a first multiplex stage are queried, and the outputs from at least some of the transceiver units one after the other be connected to the central station by a second multiplex stage over the transmission link.

According to the invention, a two-stage, multiplexed seismic data processing device is therefore proposed. As will be explained further below, this principle enables the formation of shorter arrangements or rows, so that a relatively high resolving power of the device combined with a sensitivity to relatively high frequencies of the acoustic signals can be achieved. This and many other aspects and features of the invention will be discussed hereinafter, contribute to the fact that a seismic prospecting device was created with the invention, the most ^r th equipment is superior in many ways.

In general, the seismic data processing device according to the invention is designed so that the electronics processing the signals, which are normally housed in a central registration ship is, is decentralized, d. H. into the individual cable sections which form the cable arrangement is installed. Seismic analog signals from individual seismic signals Sensors are represented digitally and by means of the aforementioned two-stage delaying the running time is Muliinlex method to a common central station transmitted over a data link.

In one embodiment of the invention, a seismic cable assembly consists of a plurality of identical seismic cable sections, each of which has a certain number, e.g. B. 10 discrete short seismic Scnsorclcmente instead of the traditional long arrangement of individual rows of sensors. There each sensor element in connection with a separate one .Signal channel works, the number of channels queried in a complete cable arrangement must be multiplied by a factor of at least 10. In a preferred embodiment 500 to 1000 data channels over a single data transmission connection to the central station within the time span of a desired sampling interval, z. B. queried and time-divided for 0.5 to 1.0 milliseconds; this interval! is called the sampling cycle designated.'

In one embodiment of the invention, the seismic cable assembly has at least 10 identical ones Cable sections on. Each section of cable contains a number of elementary seismic sensor units. A transmitter-receiver unit is assigned to each cable section. The expression "transmitter-receiver circuit" or "transmitter-receiver unit" is intended to designate the electronics contained in connector modules which form part of the cable assembly and an output circuit for the transmission of digitally represented seismic signals on the cable in addition to the common electronic circuitry for amplification and digital representation of analog seismic data input information and the Switching arrangement for successively connecting the elementary seismic sensor units with the common electronic circuit comprises the cable sections and connector modules with the transmitter / receiver units are mechanically and electrically connected to each other. The signals from each of the transceiver units are switched one after the other to the seismic cable and thus reach the central station, while signals are sent to the assigned elementary seismic sensor units are received. This is how digital signals get out all sensor units one after the other to the central station. The length of each seismic sensor unit is a A certain fraction of the length of a seismic wave, the frequency of which is the successive activation rate which corresponds to the signals on the cable, as explained below.

According to a further feature of an embodiment of the invention, there is the seismic cable arrangement from a number of active cable sections,

each of which has an interrogator, a communications link and a number of elementary seismic ones Includes sensor units. The connector modules with the transceiver units connect adjacent ones Cable sections together. Each transceiver unit has a large number of input channels, a data repeater network and a query network. The query network of each transceiver unit is connected in series with the interrogation element. Dk elementary seismic sensor units in intermediate cable sections are with corresponding input channels of the assigned, specific transmitter-receiver unit coupled, which is arranged at one end of an associated cable section. The data repeater network of each transceiver unit is coupled to the data transmission link.

An essential feature of the invention consists in a multiplex switch in each transmitter-receiver unit. The multiplex switch is sequentially operated by a control network which is connected to the interrogation network connected is. Depending on interrogation pulses from the central station, which are transmitted via the interrogation element are transmitted, the query network causes the control network to operate the multiplexer sequentially and digitally displays the analog data from the seismic sensor units as well as a self-clocking one transmits digital data word on the transmission link via the data repetition network.

In one embodiment, filters, the multiplexers, are used to determine the degree of amplification Amplifiers, the digital display devices and other electronic switching arrangements that were previously on a Registration vehicle were accommodated, which with a conventional, the seismic data acquisition system was connected, removed from the central data acquisition system and in identical, miniaturized Housed connector modules, which represent the transmitter-receiver, one of which is assigned to each cable section. The many identical cable sections are offset from one another and connected to one another via the same number of identical connector modules with transmitter-receivers. Analog signals from the elementary sensor units within a cable section are transmitted via internal data lines with the assigned transmitter / receiver unit fed into the connector component, where it is filtered, switched, checked, processed for amplification and digitally displayed in multiplex mode. Everything, what remains in the registration vehicle is the central station with a signal receiver and a recording device for recording the digital data words from the data transceivers via the data transmission link and the control logic is included to generate control and interrogation pulses, d. H. Signaie, to be transmitted to the data transceiver via the interrogation element.

The length of the elementary seismic sensor unit with three or more sensors is less than 15 m and of the seismic signals has a Nyquist cut-off frequency of 500 Hz. Generate in the course of the test process Frequencies higher than the Nyquist frequency erroneous or so-called "alias" low frequency signals, which cannot be distinguished from the desired data signal information. In the case of the invention the anti-aliasing low-pass filters, which are used to generate the Rule out high frequencies at at least -60 db (100: 1) on the full scale at 500 Hz. The -6 db point occurs at 250 Hz. The effective or critical frequency is thus half the Nyquist limit value. This, of course, is well above the seismic frequencies of interest, and the system yields thus the desired high-frequency pass band for the recording device, which in the seismic High resolution data processing system is sought.

According to a feature of an embodiment of the invention, the transceiver units have constant current supply sources and AC power is fed in at a frequency higher than the highest signal sampling frequency. A multiple conductor cable connects the individual sections of the cable and contains a data link, an interrogation link and supplementary power supply and control connections. The multiple line cable connects the plurality of transmitter-receiver units in series with each other and with the central station in a registration vehicle.

In each transmitter / receiver unit there is a large number of preamplifiers / filters, each with one input and an output provided. The inputs are with an equal variety of seismic sensor units coupled, particularly in the case of marine seismic cables within the associated cable section are attached. The preamplifier filter outputs are connected to the corresponding inputs of the multiplexer connected, its only output to the common amplifier, digital display device, buffer and output register, code converter and repeater network is coupled. The output of the repeat network is in turn connected to the data transmission link. The query member is coupled to the multiplexer and to the output register via a control network. Dependent on from an interrogation signal, which is a pulse transmitted via the interrogator to the transmitter / receiver is, the multiplexer in each transceiver is sequentially selected by the control network to one. ?., B. switched to the next channel so that the analog data are queried sequentially. The data query is gain-dependent and digitized, so that a digital data word from the output register and code converter enters the repetition network at a clock rate. When the interrogation pulse is sent to each of the corresponding transmitter-receiver units arrives, a corresponding, self-clocking, phase-coded Data word on the data transmission line

is preferably less than 6 m. The length of a ω transmitted by the central station. A second, next off

Sensor unit from z. B. 3.75 m corresponds to a half-wave question pulse switches the multiplexer in each of the

length at 200 Hz and a quarter wavelength to the receiver units to a second, i.e. next

100 Hz, based on a seismic wave speed channel for querying and digitizing the next

duration of 1500 ms. High frequency seismic event signal while a phase encoded word of

The sensor units are therefore even in the previously queried channels of the transmitter / receiver.

In the event of very low reflections at remote actuator units, it is transmitted. Be accordingly

len along the cable. over a period of a sampling cycle all analog inputs

The test rate of 1 millisecond for the electronic output channels in all transmitters / receivers is cleared

13 14 I.

The object of the invention can thus be arranged as a two-head end of the elastic section The head end of the cable is connected to a towing | the phase-coded words connected by the individual items. The cable has a multiple cable and | transmitters assigned to each cable section / a multitude of internal auxiliary input channels which | Receivers are transmitted, depending on 5 with the inputs of the transmitter-receiver unit ge | the delay time of the scanning signal, which is coupled between the cable and the wire, which is arranged one after the other from the central station to the table section. A number of 1 different transmitter-receiver units transmit auxiliary sensors that are in the vicinity of the towing vehicle I. The phase-encoded words are arranged from the individual, are connected to the internal I Hilfstingangska- channels within a transmitter-receiver unit 10 nälcn advertising connected. ; An advantageous supplementary feature results in S rend of a sampling cycle with a sampling cycle of this type by using a special filter. In the case of an arrangement, the analog signals from all 500 conventional multi-channel analog-digital 1 seismic sensor units are digitally encoded and a multiplexer with a multi-shape is connected to the conversion system via the cable during each test interval 15 number of input connections and a common , -f · of one millisecond per unit. This is how output trunking is used. Each input signal, for example, the signals from channel no. 1 of each of the connections from the multiplexer is switched in such a way that it transmits the § 50 cable sections in sequence, receives the output signal of an analog channel and the % closes the signals of channel no. 2 of each output trunk line is equipped with an amplifier £? Cable section to etc. 20 bundcn. Often, e.g. B. seismic, it is desirable, the% In an advantageous embodiment of the inventions DC component of the analog signal, the dung from each Ka ~ $ \ have the data and query compounds is added nal three to eliminate. Therefore there is a ■ ί parallel, redundant lines. A majority high-pass KC-Fi'er between each input connection % selector circuit in each transmitter-receiver unit takes to the multiplexer and the analog channel is switched. One receives a signal from two of the three lines. An error filter of this type has a series capacitance and a ρ, indicator circuit which is shunted with the data and interrogation resistance, and requires that | i connections at each transmitter-receiver unit be coupled to the multiplexer line with a load of high? · 'pelt is, indicates a broken line within the impedance is terminated According to previous practice assigned cable section, if the majority- the multiple line is connected to an amplifier with a high ί i selector circuit not three identical inputs sets 30 input impedance. The transmission link can be a broadband transmission channel with a bandwidth of at least a number of disadvantages, the most important of which are: the 100 MHz. Werl capacitance of the capacitor in each high-pass \ l According to an advantageous supplement each of ter must be relatively large and expensive. Since ti. Transmitter / receiver a data repeater 35 each capacitor requires a separate resistor |? which in turn makes a signal receiver, regenerator clear, the large number of such resistors and transducers for recording, regeneration and increases the cost of the system, and the new transmission of signals from remote stations is also a major obstacle for the mini-tied transmitters / receivers to vertization closer to the station. The necessary amplifier with high tied transmitters / receivers. There may be a delay 40 input impedance of approximately line to the output trunkline be provided in the query network, which is connected of the multiplexer, limits the standing for 'in series with the query term in each transmitter / receive available selection considerably, is connected catcher, whereby the Interrogation pulse for the For use in conjunction with a seismi _; remote station transmitter / receiver is delayed and see data processing system according to the invention '''■' thereby the data words are separated from each other, 45 filters are required to meet these disadvantages when they are from one to another, neighboring, that an improved system is provided , Cable section are transmitted. In which the capacitance of each capacitor is increased, a calibration signal from the central office is also reduced, all capacitors are transferred to a common station to each sensor unit, the antennas of which use resistance that is compared with the output multi-word signal with the input signal by 50 times of the multiplexer is connected and the ver 'to set a sensor calibration factor. The cable arrangement is in particular a Ticfseeka- drive amplifier with low input impedance erbel for stream digital data, which can be set to a data termi, so that greater flexibility is connected to nal. The cable can be reached auxiliary sensors for structural design. Such a FiI display of the surrounding water pressure and from Kater is a communted FIC high-pass filter to have connection leakage points, use in a multiplexer in a mchrkanali-Furthermore, a device can be provided which corresponds to an analog system. Each channel takes an analog that measures the strain of the active cable assembly. At the star from one source, e.g. B. a seismic sensor head end of the cable assembly is a shock absorber. Each channel contains a capacitor which is provided in the elastic section, e.g. B. in the form of e> o he with a normally open multiplex switch of a strain gauge, and a data transmitter / receiver isl, which in turn is connected to a multiplexer is connected to the head end of the elastic section input multiple line. To the multiple meatballs. The output signals of the extensometer are connected to a common resistor. An auxiliary input channel of the scanner / receiver control device closes the switch one after the other at the head end of the elastic section, so that the capacitor, its switch, is closed. The end of the outgoing cable is preferably bundled so that a high-pass /? C filter is connected to it with a transmitter / receiver unit that is formed on. In a preferred embodiment of the

Invention is the common resistance of the input resistance of an operational amplifier. The cut-off frequency of the commutated filter can thereby changed so that the dwell time of the switch is changed.

A multiplexer-commutated high-pass filter is thus an advantageous supplementary feature of the invention proposed that a plurality of analog input connections, an output connection and a multiplexer with a plurality of input connections and a common output trunk line, with a capacitor of a plurality of capacitors between each analog input terminal with the filter and each input port is connected to the multiplexer, and through a resistor connected to the common output manifold

During seismic exploration over land and water, acoustic impulses are usually transmitted into the earth directed and the reflected seismic signals are detected by a large number of seismic detectors, i.e. H. Sensors that are arranged in sensor groups or rows of sensors are recorded and displayed. In the sea seismic exploration, the sensor groups are built into a streamer cable, for example a Has a length of 3000 m and can contain 50 such sensor groups. Each group of sensors forms a single channel, each channel is connected to the seismic recording system via a separate pair of conductors. For different geological formations, different groups of sensors are required for work at shallow or great depth, and in particular different groups of sensors may be required in the same cable in order to achieve the to be able to meet the most diverse demands of geophysicists.

For deep penetration, low seismic frequencies are used and the sensor arrays consist of 25 to 35 detectors spanning a length of 60 to 90 m are distributed. Depending on the desired response characteristics, the sensors can be spatially be shortened within a group, or the sensor outputs can be electrically evaluated differently.

When exploring shallow earth formations, seismic energy of relatively high frequencies is important. For this use case, the required Groups very short. For example, they have a length of 7.5 to 15 m with, for example, 10 sensors each. If seismic exploration requires different sensor groupings for different applications, the cables must be used for each measurement for other layers of earth are exchanged. It would be desirable to have only a single cable that can hold up to 500 contains short subsets, d. H. Sets of seismic sensors that are electrically interconnected in such a way may be equivalent to any larger group required for a particular geological condition. With conventional measuring devices of this type, there would be 500 pairs of lines necessary. Cables with up to 50 pairs of conductors can still be handled by an investigation team. However, it is practically impossible to use a cable For example, to cope with 500 pairs of conductors for 500 channels in operation. Limitations on therefore, the weight of the cable and other difficulties have limited the number of channels that can be used in known seismic systems despite the known advantages that theoretically from the information via additional channels could be obtained.

The possibility of transmitting seismic signals over 500 channels to a central processing point s brings with it numerous other problems. For example, the cost of this data processing was would be very high if conventional general purpose data processing equipment were used, although in recently the acquisition costs have become considerably lower.

The transmission of 500 signals to the central station is practically impossible by using 500 separate line pairs. One possibility would be to provide 500 separate seismic data processing stations and the To send data in multiplex mode over a smaller number of channels, so that not 500 pairs of conductors would be required. However, the cost of 500 individual, active data processing stations would be far too high. Furthermore, normal carrier multiplexing would require very high frequencies, tuned circuitry, and associated electronics which are normally so sensitive and require so much maintenance as to cope with the harsh seismic operation Measurements is out of the question. The direct transmission of digital signals also brings with it many problems that lead to a loss of quality of the signals to lead. In this context it should be mentioned that the electrical integrating properties of long cables Significantly attenuates and blends conventional two-level digital signals.

Because of the numerous problems of an electrical and mechanical nature, as well as problems arising from the Data processing, the high weight and the high J5 costs, it has so far been considered impossible or at least practically excluded, usable, commercial seismic systems to pre-actual ones, in which seismic signals from several Hundreds of sensor units can be routed separately to a central station and recorded.

According to an embodiment which focuses on this problem, it should be pointed out again that the seismic data processing system according to the invention comprises a number of transmitter-receiver units which are arranged remotely from a central station. The transceiver units are connected to the central station by a broadband data transmission link and an interrogation unit. Each unit has several input channels, to each of which a short seismic sensor sub-assembly, which is also referred to as the elementary seismic sensor unit, is connected, which consists of three sensors which are separated from one another by about 2 m. A channel selection device, which is the above-mentioned multiplexer, sequentially connects the input channels to a common network that processes and digitally displays the signals. The output channel of this network sends the digital data signals from the elementary seismic sensor units (seismic sub-assemblies) to the data transmission connection for multiplex transmission to the central station. In the central station, digital data words representing the seismic signals from the subassemblies, evaluated and ^r by a Formatti> control device to new data words composed, representing a seismic signal that is obtained from a desired substantially larger seismic sensor array.

17 18

According to one embodiment of the invention, it sends a second interrogation pulse au «=

the digitally displayed seismic signals through a channel in all transmitter-receiver

self-clocking phase-encoded return-to-zero heals, etc. as mentioned above until all

Pulse code for transmission over the broadband input channels in all transmitter-receiver units transmission connection format-controlled to signal quality 5 have been queried, the interval between

to reduce loss of activity, as will be explained in more detail below. successive interrogation pulses to the same

For this purpose, the local data processing channel typically takes about V ₂ to 1 millisecond.

units in each of the various transmitters / carries

Receiver on a local clock. The local To explain further features of the invention Clock generators work asynchronously with respect to one another, the problems of achieving improved signal

but at essentially identical frequencies. Noise ratios and the increase in capacity

Each transmitter-receiver unit transmits either to precisely discriminate against neighboring geological

local data in the broadband transmission link of shear formations or discontinuities and less

or takes data words referenced below from the anomalies discussed below bound transmitter-receiver units. Data words are 15.

ter, which are transmitted by the downwardly connected transmitter-receivers.

capture units are picked up, seismic explorations are carried out again, a seismic im-

synchronized to the local clock pulse regenerated, z. B. an explosion disturbance, e.g. B. a shot fired

and to the next uplinked transmitter receiving, and a recording of the pulse catcher unit is made for final delivery to the central station, which is received by sensors or detectors at the

transferred tion. Staggered distances along a seismic channel

For purposes of identification, the data words bels. that originates from the firing point are received through a short "dead zone" in which no data is available. The seismic sensors that are commonly used The ones that are used separately to further mark the beginning of a data land are known as geophones words following a dead zone, and those that are usually used in marine seismic waves, the first bit of each data word following a dead zone are used as hydrophones marked by a positive signal edge. The pulse is transmitted into the surface of the boundary between the end of a data word, it is queried whether there are no geological layers of different natural pulse polarity inversions within two bit intervals or whether there are any characteristics that are reflected on the sensors. The self-clocking dates are dated accordingly. which are arranged above the area to be explored transfer words in constant current mode. are. The reflected signals received at the sensors

According to one embodiment of the invention, the catch, are on a recording and Central station has a core storage, and it is a processing facility in a ship or seismic Device provided to see the digital data words 35 vehicle transmitted.

to save that of the elementary seismic sen- When carrying out an exploration of this type

sensor units, d. H. the subgroups in a storage over a larger geographic area or

matrix in the sequential channel series. The prospect is the area through a grid of vermcs-

The central station also has a format control that covers the detection lines and becomes seismic profiles

records data words from the memory which are recorded from along the survey lines. In the

selected seismic sensor units are delivered mecresscismic work is a seismic stream

den and these signals to form new data words can be combined continuously through the water along one of the

ned, correspond to the desired larger groups. Survey lines are dragged and seismic

The central station can also see a read-only memory pulses from the ship at regular intervals

(ROM) to 45 len required for the data words, / .. B. after every 10 or 20 seconds, initiated

Evaluation coefficients of individual subgroups On land, the seismic cable is in the form of a series

to give up before being laid out as a compound data- of identical sections on the floor,

word can be combined. which are interconnected by electrical connectors

There is still a facility in the central station. The predetermined measurement line will be

provided that the time interval between the delivery «by the pressure waves of a seismic shot

of an interrogation pulse and the arrival of the corresponding breakthrough and the seismic data are through

corresponding data words from the transmitter / receiver input - a recording * - and data processing equipment

The time interval is recorded in an addressing device in a recording carriage. At-

code converted, which is then closed in an address memory, individual cable sections are separated

is stored, whereby incoming data words are shifted to 55 and again with the other end of the channel

train connected to their source according to the ordinal number of the bels along the direction of movement. A

Transceiver units and the number of channels within multiple switches in the recording carriage is shown in

half of each sender / receiver can be identified. advanced to a new position, causing the part of the

A control unit in the central station transmits the cable that is connected to the data processing device. Interrogation pulses to the transmitter-receiver units t, o is tied to one or more cable section lengths

via the interrogation unit. Is advanced along the surveying line by the interrogation pulses, whereupon-

checks the electronics in the corresponding transmitter - a new recording cycle is made.

Receiver units the analog signal, which is transmitted to a case of a known mecres streamer cable from If the input signal is present, the signal sample represents a length of 3000 m, for example, about 1500 sensors

phase-coded digital data word and transmits μ provided. Groups of 30 of these sensors are each

the digital data word in the central station. When these are electrically connected so that seismic Si

Control device the arrival of data words from a signal of approximately 48 seismic channels from the cable

first channel in all transmitter-receiver units. These reflected signals are

recorded and displayed in parallel tracks in order to make subterranean properties of the geological area to be explored visible. at In the absence of adjustment, the reflected signals appearing in traces created by hydrophone groups remote from the launch site are related shifted to the signals appearing in tracks which arise in the vicinity of the launch site and apparently lead to a change in the depth of the Representation of a horizontal reflective interface. According to known techniques, a movement or angle correction is applied in order to adjust the adjacent tracks on the visual display, see above that a true representation of the reflective interface is guaranteed. The value of this correction is a function of the length of time from the time of launch, the mean velocity of the seismic wave in the earth and the distance between the Launch site and the detector groups.

In known seismic reflection systems of this type, it is common to combine about 30 geophones or hydrophones into a single group, the have a spatial extension along the cable of about 30 to 90 m. In a practical embodiment such a single group has the length of In this arrangement, at least 48 pairs of conductors are used to deliver the signals from the 48 groups of sensors to the recorder transmitted, which is normally arranged on the ship or vehicle that is used to transport the seismic equipment is used.

Typically, the response range of such known systems is at the low frequency end of the spectrum, e.g. B. between about 5 Hz and 40 Hz Peak value is below 20 Hz In addition to other factors, the reduced response in higher frequency ranges contributes to phase differences in signals, arriving at spaced points along the groupings of electrically interconnected sensors which normally are extend over a distance of about 70 m. In order to avoid mutual cancellation of signals arriving at the various sensors, is intended preferably the length of the electrically connected sensor units, i.e. groupings, is proportionate be small compared to the wavelength of the seismic signals being received.

For the following quantitative consideration, a group of electrically connected seismic sensors is assumed, which is arranged on the earth's surface and has a length s . If a seismic wave traveling horizontally along the sensor group arrives at one end of the group, the travel time is.

T = s / v

where ν is the speed of sound in the medium near the group. The speed of sound in water is about 1500 m / sec, so that the transit time T of a horizontally moving wave in water for a group of electrically interconnected sensors with a length of 69 m is 0.046 seconds. For reasons of additional mechanical reinforcement in the longitudinal direction of the group of sensors, the length of the group should be less than about V _{4 of} the wavelength. The time it takes for a seismic wave to travel a wavelength is 0.04b x 4, which is about 0.184 see, which corresponds to the period of a wave with a frequency of about 6 Hz. Waves running along the Group and have frequencies that are significantly higher than the 6 Hz cut-off limit. speaks, are deleted If the length of the arrangement is exactly half a wavelength, the response is group 0, since the wave is completely deleted. As is known, seismic waves can affect a Sen sensor arrangement impinge from many angles. Example seismic waves that are reflected from deep geological formations reach the sensor arrangement in an almost vertical direction. The wavefronts are almost simultaneously through all sensors in brought a group to the display. Correspondingly, in cases of irregularities close to the surface, e.g. B. Weather conditions or differences in altitude, the upper blocking frequency is practically infinite. On the other hand, the direction of propagation is approaching seismic waves emerging from very shallow layers of the earth are reflected, the depth of which is significantly smaller than the distance from the launch point to the sensor arrangement, the horizontal, so that the previous analysis can be used for horizontally traveling waves.

For example, let the relatively flat angle of incidence be one

seismic wave coming from a layer 300 m deep is reflected, with respect to a sensor arrangement that 3000 m from the termination point is considered

Seismic reflections are from shallow layers

relatively rich in high frequencies (100 to 500 Hz) used to analyze high resolution details geological properties are useful. Unfortunately, lost / ended seismic systems are at the fore these days a length of the sensor arrangement of 30 to 90 m se-

J5 selectively applies to very low frequencies, with frequencies below 20 Hz dominating. The desired High frequency waves from shallow layers of the earth are generated through the use of long sensor arrays turned off.

The preference for the lower frequencies in conventional large area mining systems is limited of course, the sensitivity and performance of the system in viewing and resolution closely spaced geological layers, smaller discontinuities or other important properties that do not extend far in space, especially in the shallow part of a geological section. Since a lot of prospecting work is of significant interest on spatially smaller areas are concentrated, it becomes more and more important geological

5u to use high resolution surveyors for detailed work.

Sensor groups of considerable length have preferably been used in reflection seismics to / wipe out useful and undesired interference signals to be able to divorce. The general theory that the The relationship between the length of the group and the signal-to-interference ratio can be, for example, the Article "The Moveout Filter" by Savet, Brustad and Sider, taken from "Geophysics", January 1958.

From time to time attempts have been made to improve the radio frequency interference in seismic sensor devices by making them very short Groups were used. However, the most important result was a considerable deterioration data quality due to the unavoidable Reduction of the Signs I-to-noise ratio.

Some seismologists have considered the possibility of increasing the Sijnal-Stör ratio

an acceptable value to bring that the number of Sensor groups is increased significantly, whereby in practice the number of individual sensors is retained, however, were divided into more but shorter groups. The interaction of two fundamental factors however, makes such an approach practically useless. The first factor had to do with that Processing operations. To determine the normal motion corrections needed to assemble of the data used when they are received, correlation operations (or equivalent Events) is used between sets of individual seismic traces (data from individual groups) will. With data from short groups, the poor signal-to-noise ratios have the capability this method decreases. Furthermore, the extraordinarily high number of individual data records brought about an increase in data compression costs to values that are from a commercial point of view were not acceptable. Furthermore, there have been many other problems and difficulties that the practical Make application of such a system impossible.

In particular, another difficulty that arises from the use of shorter groups of sensors it can be seen that, for example, if a Full length seismic cables of 2 miles are used and the sensor density is unchanged the number of signal channels that must be connected to the recorder in order to keep the The order of magnitude by which the length of the group is reduced. This means that about 10 times so many pairs of conductors must be used if the lengths of the groups are significantly reduced should, of course, this increases the number of contacts very crucial, which are required for plug connections, which are used to couple cable sections are used, which are produced according to previously known techniques. Furthermore, the large number would of ladders significantly increase the weight and dimensions of the cables and increase their flexibility reduce to usability.

Typical prior art systems considered in understanding the problem discussed here can, are in US-PS 31 33 262, in the two Overlapping hydrophone scattering areas in a single marine cable are described in the U.S. Reissue PS 25 204, the US-PS 30 96 846, which a certain evaluation of seismic signals from different Seismic sensors to achieve a directional effect teaches, in US-PS 33 46 068, the direction-sensitive seismic transmission and reception arrangements describes, in US-PS 36 89 873, the delay and Evaluation circuits for seismic signals can be found and explained in US Pat. No. 3,613,071 from which the use of two groupings of geophones with different interval and results in different test rates

To solve this problem, the present invention is a seismic system for the systematic Exploration of extensive trenching suggested that is responsive to much higher frequencies than such Systems as they have been used up to now. In particular, relatively short elementary Sensor units, e.g. B. Hydrophones, over the full Length of seismic cable of normal size can be used. With a special execution form Of the cable, only three sensors are used in a basic sensor unit, which are 1.875 m apart are cnlfernt, so that there is a total length of the elementary sensor units of about 3.75 m. From equation (A) and assuming water as the medium to be used, takes into account the fact that 3.74 m 'Λ of a full wavelength of 150 m, a period of the wave of 0.010 seconds corresponding to a cutoff frequency of 100 Hz. In the case of an angle of incidence for flat reflections of about 60 °, the upper limit frequency is 200 Hz. Noise signals wandering horizontally with a frequency significantly above 100 Hz are attenuated, which is desirable to improve the signal-to-noise ratio. By using short, elementary sensor groups is the upper frequency lock from 6 to 100 H /. been raised for seismic while that nahc / .u progress horizontally. With an even shorter length of the sensor unit, an even higher frequency response will be achieved obtain. A sensor unit with a length of 1.95 m increases the response for horizontal Progress to about 200 Hz. With a slightly larger length of the elementary sensor unit, e.g. B. 7.5 m, the response would be reduced to 50 Hz, which of course is still a substantial improvement over this currently commercially used mining systems.

It has been found that larger group lengths are required to achieve high signal-to-noise ratios to achieve each of a plurality of individual traces that determine the detection cross-section, thereby obtained can be that the signals from the desired number of elementary sensor units are added with certain time delays so that all reflection signals that are detected in a track should be totaled with the same phase. These

j5 delays are used in the course of a kill Controlling the groups that create the tracks is changed. The delays create an electrical effect quasi-parallcle wave front at the grouping, so that the phase velocity of the signal along each grouping is effectively infinite.

Since the slope of subterranean reflective geological interfaces is generally not known to the geologist prior to conducting the seismic survey, it is usually necessary to assume in advance that all reflectors are horizontal and to abandon time delays equivalent to those for a horizontal one Reflector would apply, which causes the signal recorded at any point in time and at any distance from the launch site.In so far as such programmed time delays do not correspond to the real signal delays, the signals are summed out of phase the simple, simultaneous summations produced by the fixed groupings of a known type. Accordingly, the upper frequency response limit will be considerably higher.
As will be explained in detail below, the individual recordings of data from separate sets of sensors that form the groupings are retained so that, after initial processing in the manner described above, the time delays forming the groupings are again programmed.

mated and given up again, so that the white front is aligned more precisely and effectively parallel to the horizontal in a step-by-step approximation (i.e., parallel to the grouping). This allows

get a summation that has a far better phase match and ensures a much higher high-frequency separation point.

The invention enables shorter lengths of sensor units to be used with full length cables, as required for expedition prospecting, so that a transfer of the resulting large Number of signals on the recording device is possible without an exceptionally bulky, heavy one and expensive cable. This is achieved in that the electronics are included in the cable to carry the signals to be recorded by each of the relatively short elementary seismic sensor units and in multiplex operation to process and via a single data transmission line, e.g. B. a channel or a strong reduced number of channels to the recording and processing device at one end of the cable transferred to. The check rate for those in multiplex mode treated signals should be more than twice the highest frequency to be transmitted. Corresponding With the system explained here, a test rate in the order of at least 500 and preferably used 1000 or more samples per second.

In systems, for example in the system according to the invention, in which higher frequency seismic signals are used, certain difficulties arise that are not or at lower frequencies not occur to that extent. In particular, for example, if a geological formation that has a has a large angle of inclination to the horizontal, is encountered during a geophysical exploration, the high-frequency signals of 100 or 200 Hz through the long groups, as in the prior art used, can be dampened to a high degree. There can also be a significant difference in amplitude and in the frequency content in the received signals from a layer with a fairly large angle of inclination, depending on the direction and distance of the seismic sensors or the orientation the seismic group or cable relative to the launch site.

This problem is solved by sensor arrangements that are sensitive depending on the direction. In particular, will the higher frequency energy characteristic of smaller geological discontinuities and formations, displayed more quickly by the direction-sensitive groups, and the system also delivers in the event of an extended one Exploring no inconsistent results.

In the geophysical exploration method according to the invention, at least two groups of sensor families (hydrophones and geophones) in a single seismic cable and a geophysical survey is carried out so that the directional sensitivity Each group is changed individually to selectively receive signals from a seismic To receive disturbances, which are reflected individually and one after the other from progressively deeper layers. The outputs of the groups are processed one after the other so that geophysical cross-sections can be displayed are.

In a reflection seismographic exploration method, seismic disturbance is initiated, at least two directionally sensitive seismometer groups are accommodated in a cable, and geophysical exploration is carried out by individually changing the directional sensitivity of each group in the course of recording reflections of the seismic disturbance , whereby group signals are obtained.
As stated above, the seismic cable of the invention includes a large number of approximately uniformly offset elementary seismic sensor units, and signals from each of these units are transmitted over the cable to a seismic data processing device rather than being electrically combined within the cable. In known marine cables of about 3000 m length, as already mentioned above, about 1500 hydrophones are used, and the signals from groups of about 30 of these hydrophones are thus combined

r> ned that they form a single channel, making seismic Signals of 48 channels can be transmitted from the cable. In contrast, in the case of the invention The use of approximately the same total number of seismic sensors is envisaged, however only the outputs of a few sensors combined to form a signal from an elementary sensor unit and seismic signals are transmitted from the cable containing several hundred of these elementary ones Represent sensor units. These seismic signals become a fewer number of directional group signals combined, the adjacent areas of geological structure against which the individual Groups are directed, the instantaneous direction is continuously changed. These Group signals are then combined in such a way that they form a geophysical representation of a Cross-section of the earth's strata.

The central station, in which a group form device carries out a suitable combination of data,

3 ^r > sits a high capacity recording device, e.g. In the form of a video recorder to store the digital signals representing seismic signals from all of a plurality of elementary sensor units in each of the many sets of such units within the seismic cable. The recorded digital signals are then put together by a second group shaping device by combining a plurality of direction-sensitive sensor group signals along the line of exploration, where-

«Through a series of geophysical traces Individual alignment of the groups to be formed on expected points of reflection, which arise as a function Change the reflection time after a shot. This technique enables the energy to be recorded more selectively, those at changing angles from neighboring tracks through the geophysical to be explored Build-up to be reflected on corresponding neighboring groups in the longitudinal direction of the cable. In connection the traces obtained from neighboring groups are converted in the same way, to get a complete geophysical cross-section.

It has been found to be useful, if possible the initial signals picked up by the first part or parts of the seismic cable, which of the launch point are closest to interrogate with a higher sampling frequency. In a later Time segment of the recording cycle for the same shot when the reflections are the more distant parts

b5 of the cable becomes the sampling frequency for each elementary sensor unit reduced along the entire cable.In particular, during the initial period, if reflected seismic signals only sensor

Ren in the first half of the cable, each of the sensor units in that part of the cable with double Sampling frequency compared to the normal frequency are queried, and the sensor units in the second half of the cable are not scanned. With this arrangement, the recording apparatus records naturally the same number of total samples during the sampling cycle because during the first part of the Cycle the sensor units on the first half of the cable polled twice during the normal sampling interval while in the later part of the scan cycle all units are during the normal test interval can only be queried once. After a time interval that is smaller than an interval that the reflected signals need to reach the second half of the cable 7.u, the system switches to the second operating mode above, in which all sensor units are queried with a slightly lower frequency. For example, if the normal sampling time for the entire cable is one millisecond per sample, so can during the Starting interval the sensor units in the first half of the cable with a frequency of two samples can be checked per millisecond, while no check from the second, more distant part of the seismic Cable is made. During both parts of the cycle, the recorder will take samples with one Frequency equal to the product of 1000 samples per second, multiplied by the total number of sensor units in the cable. The one from the nearby Initial signals picked up part of the seismic cable include higher frequency components of the relatively short distances covered by the seismic waves, and these are higher Frequencies can be detected sufficiently well with the higher sampling frequency. If so samples from the closer part of the cable at a frequency of 2000 samples per second instead of 1000 samples per second are queried, the maximum information that can be transmitted approaches that of 1000 Cycles per second occurs instead of 500 cycles per second, which is mostly due to the lower sampling frequency is equivalent to. Therefore, the higher sampling frequency enables even higher resolution for selected parts of the geological section to be explored.

In one embodiment of the invention, the use of 10 or more groups is contemplated that are staggered along the cable, each set having a plurality of elementary sensor units and the signals from the sensor units are combined so that each group is selected with Signals is applied that are delayed so that the group in question is oriented towards neighboring underground locations in the area to be explored. The delay between the units for different signal groups is different and is time dependent changed so that signals from progressively deeper layers are recorded. The resulting Tracking signals can then be combined using standard motion correction and visual display techniques used to cover the full seismic intercept.

This measuring principle just explained is made usable by a special cable electronic circuit, their alternating current supply at high frequency, d. H. above the seismic signal band of interest, works through special amplification, digital representation methods and test circuits and special Data processing circuits in connection with the group form device, including a matrix memory arrangement, save the seismic signal samples in relation to individual "time windows" and finally by very fast working circuit

^r ) groups, an evaluated combination of selected samples is achieved in order to form the seismic trace signals from which a respective cross-section of the explored area is obtained.

After the individual features of the invention have been explained, specific reference will be made below Points of the basic construction are discussed, as well as how the various characteristics to achieve contribute to the desired result. As mentioned at the beginning, one of the problems to be solved is the improvement

! 5 reduction of the signal-to-noise ratio and an increased Sensitivity and indecisability of the signals obtained in the case of large-scale seismic surveys Grazes. These goals are first achieved by improving the high frequency response of the seismic system is improved. The factors contributing to the improved high frequency response contribute are essentially

1. the small mutual distance between the elementary sensor units,

2. the generation and transmission of large numbers (of the order of several hundred) seismic signals over a seismic cable of a given length,

3. The combining of signals from the elementary seismic sensor units with itself continuously changing delay times to achieve direction-sensitive group signals, which always indicate the depth from which the arrival of the reflected signals is expected, and

4. the immediate installation of electronics for amplification, digital display, multiplexing in two stages, correction, testing and further processing of the high-frequency seismic signals in the cable.

The seismic data processing system according to the invention is capable of resolving seismic Large mining systems roughly double by the upper limit of the pass band of the seismic System is raised by at least an octave. In particular, the upper -6 db point was the cutoff frequency in seismic systems up to now at around 40 Hz, compared to at least 80 Hz for that for the system and the method of the invention.

Below is another beneficial supplement of the invention explained Since the invention relates to detection devices for seismic analog signals in which the outputs are multiplexed from a large number of channels receiving signals are switched and the amplitude of the signals under test is converted into digital words, it should be noted that that in conventional, multi-channel analog-to-digital conversion devices a multiplexer with a plurality of input connections and one common Output trunk line is used. Each input connection to the multiplexer is connected in such a way that that it receives the output signal from an analog device, e.g. B. a seismic sensor Often, as in seismic engineering, it is desirable to use the DC component of the analog signals transmitted by received on each multiplexer channel. For this reason, a DC blocking

capacitor between each input terminal / um Multiplexer and the analog signal source switched. The multiplexer multiple line is equipped with a signal setting and amplifier network, hereinafter referred to as SCAN.

For reasons known to those skilled in the art, undesired voltages are applied to the DC blocking capacitors and the SCAN generated. The undesired voltages can lead to thermoelectric effects, PeMier effects, offset drift in the amplifier stages, Field effect transistor switches (FET) with feed-through capacitors and Ableitungswiderländcn between their control and switching elements, etc. lead. The problem of unwanted tension is particular acute in seismic engineering because the incoming analog signals have an extremely wide dynamic range Cover area, for example up to 1200db (1: 1,000,000). The unwanted voltage is often of a magnitude that is comparable to that to be detected seismic signals.

In a typical, known, multi-channel seismic facility, each channel has a DC blocking capacitor connected to one terminal of a normally open multiplexer switch while the other terminal of the switch is connected to the multiplexer output trunk is. The multiple line is connected to the SCAN, which is a control device for successive Having closing the multiplexer circuit. The capacitor whose switch has been closed transmits the undesired voltage via the SCAN to an evaluation device, for example an analog-to-digital converter.

In the present case, the blocking capacitor of one of the input channels to the multiplexer is grounded, so that this channel becomes a measuring channel. The undesired voltage generated across the capacitor in the measuring channel is essentially the same as the interference voltages generated across the capacitors in the multiplexer channels receiving the signals because all the capacitors and switches are identical. A key memory circuit (S / H) or test and hold circuit has a series capacitor, and a normally ungrounded bypass switch is connected between the output of the SCAN and the input to the analog-digital converter, which represents the evaluation device. The charge of the blocking capacitor in the measuring channel is periodically, namely during each sampling cycle of the multiplexer, transferred to the series capacitor in the S / W circuit, but with opposite polarity and preferably the same amplitude as the test voltage.

The invention provides a device for initiating a desired switching sequence in at least one of the operations, a first signal is transmitted via the first connection to the plurality of data acquisition units. A second signal is transmitted over the second connection after a certain time delay following the transmission of the first signal. The signal running through the / .wide connection overtakes the signal running through the first connection at the special terminal detection unit selected for a switching process. When the gleichzeitigc presence of both signals is displayed at the selected Datenerfassungseinheil that ^c desired switching sequence is initiated. The first signal "can be characterized by one of a plurality of properties or states. When the state of the first signal is identified, a desired switching process is initiated in all data acquisition units one after the other as a function of the respective state of the first signal.

This feature forms part of the facility for transmission and selective control of submultiplexed treated seismic data via a signal transmission link to a common central station that has the signal processing device. A variety of data acquisition units is available with the central signal processing device via the Signal transmission link coupled. The data acquisition units are equidistant from one another in a grouping with increasing distances along the transmission link arranged offset from the central station and the processing device. The signal transmission link comprises the interrogation channel, the control channel and the data channel. The signal propagation time through the query channel is different from the transit time through the control channel.

Each data acquisition unit is the plurality of analog input channels, which acts as the channel selector working multiplexer, the analog-to-digital converter and the storage register allocated for the output signals, as mentioned above and described in detail below. The input signals from the input channels are multiplexed treated, converted into digital form and temporarily stored in the storage register for the output signals saved.

The output signal storage register of each data acquisition unit, d. H. Transceiver unit is with the recording device in the central Processing device of the central station coupled via the data channel of the signal transmission link. The data acquisition units are also equipped with an interrogation signal and provide first and second signal coincidence detectors.

The transmits at selected sampling intervals

from a large number of data acquisition units, in the 55 control unit a query signal in sequential order Practice the above-mentioned transceiver unit via the interrogation channel to each data acquisition unit th, suggested. The registration units are in a desired scheme at locations remote from ei

a central signal processing device at the central

sequentially. The interrogation signal is characterized by one of a variety of properties, if the signal characteristic identiHzierende means provided len station, a control signal transmitter to a Abfragesigna having a first property anaufweist The detection units corresponds essentially to the multiplexer is reset When the equally spaced along one or more transmission links, which are also referred to as transmission channels, arranged. The detection units are connected to the control signal transmitter via b5
two signal transmission links connected.
The transit time of a signal through the first connection

is shorter than that through the second connection. During signal property identifying device a signal with a second property, the multiplexer is switched on and outputs data from the Output signal storage register in the data channel for transmission to the: recording device. Additionally receives, regenerates and transmits any given data acquisition unit, i. H. Transmitter-Emofancer Unit

Data arriving from more distant entities.

At a preselected time that is different from the time of transmission of the interrogation signal. a control signal can be transmitted via the control line by the control device. The preselected time difference is (n-1) R, where π is an integer representing the rank of the nth data acquisition unit and R is the signal propagation time difference through the interrogation and control channels between any two data acquisition units.

The interrogation signal is preferably a pulse of preselected duration, i. H. Broad. The property or the State of an interrogation signal which is used as a control parameter in the embodiment described.

The simultaneous arrival of an interrogation pulse in the first state at a selected data acquisition unit and a delayed short control pulse via the first control channel leads a second desired switching sequence.

Furthermore, it is a beneficial addition to the Invention possible, a third desired switching sequence in a selected data acquisition unit by the simultaneous arrival of an interrogation pulse in the first

ίο State via the query channel and a delayed one short control pulse via the second of the three control lines.

narrower pulse is defined as having a second property or state. The width of the narrower pulse is preferably about that

In addition, a fourth desired switching sequence in a selected data acquisition unit can be performed by the is the width of the pulse. A broad impulse is defined as 15 simultaneous arrival of an interrogation impulse in the first an ersie property is defined, while one state is defined via the interrogation channel and one is delayed

short control pulse can be initiated via the third of the three control lines.

For secure data transmission, it is beneficial if half the width of a wider pulse. The width 20, according to a further addition to the invention, that of a wider pulse is preferably fewer query and control pulses repeated on the data than half the preselected sampling interval. frame units in short sampling intervals

In a further embodiment of the invention, times that are less than one millisecond are switched a desired switching sequence in the components of a can. The width of the control pulse is set in a desired subgroup of successive 25 so that the desired switching sequence is initiated in at least ei data acquisition units; the subgroup nigen of the data acquisition units takes effect. For example, half of the units can be selected from the large number of data acquisition units selected unit and a last selected unit processing unit are activated. the number of on. An interrogation pulse in the first state is generated by the jo Pulse transmissions can be of the order of magnitude of central processing device through the interrogation channel transfer. After a selected time delay becomes a long control pulse via the control channel transfer. The leading edge of the long control pulse overtakes the query pulse in the first state of the first selected unit and intercepts it. the The trailing edge of the long control pulse overtakes the interrogation pulse and passes all of them before the interrogation pulse Units beyond the last selected unit.

The length of the long control pulse is equal to 40 to complete one recording cycle. the first integral multiple of the signal transit time difference query and control pulses are repeated on the through the two channels between any two Da data acquisition units in preselected scanning interval acquisition units. The desired switching sequence is transmitted after a first recording only in the units in which the interrogation and cycle has been initiated. The breadth and the duration Control pulses are present approximately at the same time. The 45 of the transmission of the control pulse are entered in this way

500 to 1000 such transmissions, extending over a time period of V2 up to 1 second. in the Following this, the width of the control pulse becomes like this set so that the desired switching sequence is made effective in all data acquisition units. Same the pulse transmission repetition interval becomes timely increased to a millisecond or two or more. Additional impulse transmissions can then be made by 1000 to 6000 or more such transfers.

first integer multiple is equal to the number of components minus one that is in a subgroup available. The selected time delay corresponds to a second integral multiple of the signal propagation time difference between any two data acquisition units, the second multiple being equal to Is the number of units that lie between the first selected unit and the central processing device.

According to a further feature of an embodiment of the invention, three parallel control channels are provided. A majority voting circuit on each data acquisition unit is coupled to the three control channels. A delayed long control pulse is transmitted via the transmit three control channels in parallel. The simultaneous recording of an interrogation pulse in the first state a data acquisition unit via the interrogation channel and a long control pulse via at least two of the three control channels initiate a first desired switching sequence.

According to a further feature of this embodiment of the invention, a delayed short control pulse is transmitted over the first of the three control lines. stcllt that a desired switching sequence in a first Subgroup of data acquisition units that contain a preselected number of building units, is made effective. After the first record cycle has been completed, a second Recording cycle initiated, and the width and duration of the transmission of the control pulse are set so that a desired switching sequence in a second Subgroup of data acquisition units effective is made. The above-mentioned steps can be repeated a number of times so that an apparatus is obtained which has a desired switching sequence in successive subgroups can be made effective by subsequent data acquisition units

M) the.

With the invention it is also possible to keep the width of the control pulse constant for each recording cycle to wrap. For each drawing cycle, the duration of the transmission of the control pulse is related to

b ^r , the transmission duration of the interrogation pulse by another multiple of the signal propagation time difference, ie delay, delayed between any two units. For example, by enlarging

The delay is increased by a multiple of a unit after each recording cycle made effective in succession, thereby achieving the desired, prescribed curling ability will.

By using a single, time-delayed, two-stage, multiplexed telemetry connection, it is now economical and practically possible to use an in principle unlimited number of seismic sensor units. the Using a single telemetry link reduces the number of lines of seismic cable required by multiplexing it twice far that it is now possible to have 500 to 1000 separate To use daienkanal.

The invention is explained below in conjunction with the drawing on the basis of exemplary embodiments

F i g. 1 shows a schematic overall view of an embodiment of a seismic device which is shown in FIG Water is operated and is towed behind a vehicle;

2a to 2d are cross-sectional views of a section through the seismic cable of Figure 1;

3a to 3d cross-sectional views of a connector module with transmitter / receiver as part of the seismic cable according to FIG. 1;

Figure 4 is a circuit diagram of the power feed connections for the transmitter / receiver;

F i g. 5 is a schematic circuit diagram of a transceiver unit;

F i g. Figure 6 is a schematic diagram of the majority voting and error indicating circuits;

F i g. 7a is a schematic representation of a pressure transducer;

7b shows the electrical connections of the auxiliary channels;

F i g. 8a is a sectional view of an end portion; 8b shows a schematic representation of the electrical connections in the end section;

Fig. 9 is a cross-sectional view of the insertion cable section;

Fig. 10 is a timing diagram showing one type of self-clocking code for the transmission of data words;

F i g. 11 is a timing diagram for one sampling cycle; Fig. 12 is a timing diagram showing the sequence of interrogation signal and data signal transmission with respect to reproduces two cable sections;

F i g. 13 is a timing diagram illustrating the activation of three successive transceiver units, but no other unit;

14 is a schematic block diagram of a typical filter circuit for an analog-to-digital seismic signal processing system;

Fi g. 15 is a schematic illustration of an embodiment of a commutated high-pass filter;

16 shows a schematic representation of an analog-digital converter device in which the commutated filter according to FIG. 15 is used;

17 is a schematic block diagram of a seismic data processing system;

! • 'ig. 18 is a schematic representation of the Kleklronic contained in the transmitter-receiver unit;

19 is a detailed schematic representation of the Repeat networks in the transceiver unit of Fig. 18;

F i g. 20 Zett diagrams to explain the mode of operation of the system according to FIG. 17;

Fig.21 is a schematic representation of a group molding device as it is in the central station of the System is included;

Fig. 22 modifications of the shape of different Pulse codes;

F i g. 23 is a diagram of a marine seismic exploration system;

ίο Fig. 24 and 25 are diagrams showing the response of a seismic cable group at different frequencies as a function of dip or slope the underground layers from which signals are reflected;

Fig. 26 is a diagram showing the configuration of a indicating typical seismic grouping;

F i g. Figure 27 is a diagram illustrating a tapered array;

Fig. 28 is a graph of the square mean value of the speed of the reflecting th seismic waves as a function of the transit time of these waves;

F i g. Figure 29 is a simplified diagram used in calculating the delay on adjacent sensor units that are one of multiple units form existing seismic grouping;

30 shows the response of the seismic grouping as a function of an angle of inclination;

Fig. 31 is a block diagram of an embodiment the large-scale seismic data processing facility;

F i g. 32 a block diagram of the cable electronics and the seismic sensor units;

F i g. Figure 33 is a detailed block diagram of an array forming device which forms part of the circuit according to Figure 31;

34 is an overall block diagram of the specific data processing equipment used in executing the beam steering array forming device is used;

F i g. 35 is a diagram showing the formation of groupings in the beam steering apparatus of FIGS Figures 31 and 34 show;

F i g. 36 is a simplified block diagram illustrating a typical digital to analog conversion system;

F i g. 37 shows a simplified schematic block diagram of such a device;

F i g. 38 is a diagram of a modified circuit similar to that of FIG. 37 corresponds, in which the filter after however, Fig. 16 is inserted into the input channels;

F i g. 39 is a block diagram of a variable gain binary gain system;

F i g. 40 is a schematic diagram of an amplifier stage of the system of FIG. 39 with noise extinguishing device;

F i g. 41 and 42 are schematic representations of the principle of extinguishing the noise, as is the case with the circuit according to FIG. 40 is used;

43 shows a greatly simplified, schematic Darbo position of the multi-channel seismic data processing system;

Figure 44 is a block diagram of the signal conditioning logic contained in each transceiver unit; 45 shows a circuit diagram of the signal property b ^r > identification device and the first and second signal coincidence detectors in a transceiver unit;

Fig.46 a circuit arrangement for delaying the

Transmitting a control signal subsequent to the transmission of an interrogation signal and to give the control signal a time offset;

47 an expansion of the representation according to F i g. 43, showing seven data acquisition units, of which three successive units are activated, as well as a time diagram which shows the time relationships of the control and interrogation pulses in FIG with respect to the transceiver units; and

F i g. 48 shows a modified embodiment of the control and interrogation circuit according to FIG. 45.

According to Fig. 1, a ship 10 is towing a seismic one Sensor cable assembly 12 through water 14. The seismic sensor cable assembly 12 is elastic Shock absorber section 16 and an insertion section 17 connected. The trailing end of the cable assembly 12 is provided with a short end section 18. The cable assembly 12 is divided into individual active cable sections 20, each of which is 60 m long. everyone Connector module 13, which contains an electronic assembly, which is referred to as a transmitter-receiver unit, connects active cable sections 20 to one another both electrically and mechanically. A typical seismic sensor cable assembly 12 consists of 50 or 50 more active sections 20 and can have an overall length of 3000 m or more. Each cable section can contain ten elementary sensor units 21, each of which represents a single channel. The entire cable arrangement 12 therefore generates output signals from 500 individual channels. The sensors can be hydrophones when the illustrated embodiment is a marine seismic cable.

The signal outputs from the elementary sensor units 21 are connected to one of the transmitter-receiver units coupled, which transmits the signals to a central station 2 on the ship 10. The central station 2 contains a control circuit 4 for the transmission of query, command, power and test signals and a device 6 for receiving and recording digital Data words from a data link in the cable.

As the ship tows the cable assembly 12 through the water, it creates a seismic sound source 19, e.g. B. a compressed air pulse source (Luftkanonc) or a gas explosion device, at intervals seismic waves in the water. These waves follow suit down through the water 14, e.g. B. along the beam path 15 and hit the water bottom surface 22, where they move in the direction of the path 23 due to the different speeds between water 14 and earth layer 24 are broken. When penetrating the ground, the acoustic waves set continue along the refracted beam path 23 and are reflected by a subterranean layer 26. The reflected waves return along the beam path 28 to the bottom surface 22 of the water and continue their way up along the beam path 30 from there. The reflected waves are through Detected sensor units 21, which convert the reflected acoustic waves into electrical signals. the acoustic waves also take other beam paths, e.g. B. 31 —32—34—36, where they are replaced by sensor units, / .. B. 2Γ, which are further away from the ship 10 are as the sensor unit 21. Although similar beam paths between the sound source 19 and each of the 500 Basic seismic sensor units in the seismic cable assembly 12 are only two such paths are shown for reasons of clarity.

2a shows a schematic longitudinal sectional view of the leading end of an active seismic cable section 20. For reasons of the graphic representation, the longitudinal dimensions are significantly shortened been. The section consists of an outer plastic skin 40, three tensile load components 42, 43 made of steel (the third component is not shown), a plurality of end wall spacers 44 and one

ίο end spacers 46 at each end of the section. The plastic skin 40 has an inside diameter of 7 cm and a wall thickness of 0.475 cm. The end wall spacers 44 are 60 cm apart inside the plastic skin 40 for internal support intended. Each bulkhead spacer 44 has three holes 48, 48 ', 48 "(Fig. 2b) to pass through of the loading components and a central hole 50 for the passage of the connecting line cable bundle 52 on. The skin is over with the release end wall 46 Steel straps set 54.56. The entire skin is with filled with light kerosene, which gives a neutral buoyancy in water.

A plurality of sensors 23, e.g. B. hydrophones are in a distance of 2 m each within the cable

2 ^r > section 20 arranged. Each sensor is supported between two closely spaced end walls 44 by means of connecting links of a conventional type. Each cable section has at least 30 seismic sensors 23. In one arrangement there are three sensors 23 connected in parallel by local data lines 58, 60 so that they form a single instrument and thus an elementary seismic sensor unit 21. Since the sensors are offset by 2 m from each other, the length is the elementary sensor unit 4 m and the separation between group centers is 6 m. The local data lines 58, 50 are connected to cable bundles 52 and carry the signals from the sensor units to corresponding pins of a multi-conductor connector 62. With this arrangement, each elementary seismic

4i> see sensor unit from three sensors signals into one single, shared data channel. The parallel connection has the effect that the electrical outputs of the individual sensors 23 are algebraically summed up. The summation of the signals leads to amplification

4 ^r > desired, systematic, reflected signals and for the suppression of undesired, random noise signals, provided that the seismic white front runs approximately parallel to the plane of the grouping. In this ideal case, all sensors 23 "see" into the

w elementary sensor units 21 or 2V (Fig. 1) the wave front and record the seismic waves in phase. The angle increases as the distance from the source increases. In addition, the jet path angle depends on the inclination of the bottom surface 22 in the water, the reflective interface 26 and many other factors.

A wavefront, e.g. B. 35, which can be a wave crest, progresses so that its extension is perpendicular to the beam paths 30,36 remains. When the wave crest 35 strokes over the cable assembly 12, it will be first detected by the sensor unit 21, and a little later from the sensor unit 21 '. In the moment in which If the crest 35 of the wave hits the scnsorcinhcit 21, it is possible that the wave trough of a preceding one

h ^r > wave is still scanned by a Scnsorcinhcit 21 '. If all sensors between 21 and 21 'were connected together in a long group, signals from the sensor outputs would instead weaken each other

strengthen. It is therefore desirable that the length of one individual elementary sensor unit short compared to the length of the seismic signal with the highest frequency of interest isi.

The wavelength of a seismic wave, as picked up by a group of seismic sensors that are electrically connected to each other, depends in a complicated way on the angle of inclination and depth of the underground layers of the earth, the speed of the seismic wave, the distance between the acoustic source and the sensors and many other factors. Consider a group of electrically interconnected seismic sensors located on or near the surface of the water. The group has a length X. If a horizontally traveling wave (angle of incidence = 90 °) hits one end of the group, the time T is that the wave needs to traverse the group

T = X / V

where V is the acoustic velocity in the propagation medium. At a speed in water of 1500 m / sec and a group length of 69 m of the known type, the transit time for the wave is 0.046 seconds. For an additive response in the longitudinal direction of the sensor group, the group length should be less than '/ «wavelength. The running time of a wave is therefore 0.046 ■ 4 or about 0.184 seconds. This period corresponds to a cutoff frequency of about 6 Hz. Waves arriving at the end of the group and having frequencies much greater than the 6 Hz cutoff frequency tend to be severely attenuated.

In the system shown, the length of an elementary sensor unit is 4 m Wave is 0.0026 see. The frequency is a quarter of a wavelength

/ = 1 / (0.0026 x 4) = 96.1 Hz.

Using a short elementary seismic sensor unit or group is the upper limit frequency has been significantly expanded. Take a 30 "angle of incidence for a wide-angled, shallow one Reflection signal that is picked up in the area of the lindes of the cable arrangement, the upper Cutoff frequency raised to

f = 96.1 / sin 30 ° = 192.2 Hz.

In addition to the seismic sensors 23, auxiliary sensors, for example pressure transducers 64, loss indicator conductors 66, 68 and a water break indicator device 72 are provided in the cable section 20 in the vicinity of the leading end according to FIG. 2a. Electrical connections from the additional sensors are connected to the bundle of cables 52 and transmit sensor output signals to corresponding pins of a connector 62. In a typical section of cable 20, e.g. B. ten Datenkanälc and three auxiliary channels available.

FIG. 2c is a cross-sectional view of the cable section taken along line 2c-c and showing the configuration of the seismic and auxiliary sensors within the outer layer 40. The references in FIG. 2c correspond to the same reference symbols in FIG. 2a. l · i g. 2d is a cross section through an end wall 44 along the first line 2cl-d according to FIG. 2 and shows holes 48 for the loading component 42 and an opening 50 for the cable bundle 52.

The cable sections are connected to one another as shown in Fig.3a. In this illustration, the ends of adjacent cable sections are symmetrical, so that only one end will be described in detail. The loading components 42 and 43 extend through an end end wall 46 and are terminated by draw hooks 45, 47 or the like known per se. The cable bundle 52, which extends through a central opening in the end face wall 46, ends at a connector 62.

A connector module 13 is provided between adjacent sections 20 . Each connector module 13 contains a transmitter / receiver unit, the purpose of which is to receive analog signals from seismic sensor units and auxiliary sensors, to display the signals digitally and to transmit the digital data to the ship 10 via a data transmission connection in the cable bundle 52. The connector module 13 has an end wall connector 76 at each end which mates with a connector 62. The mating connector plugs enable the sensor units to be coupled to the inner transmitter-receiver unit and provide a device for coupling the transmitter-receiver units in series with the transmission link, the interrogation unit, the power and test signal channels in the connecting cable bundle 52. Short loading components 78, 80 ( a third corresponding component is not shown), which are closed by pulling hooks 82, 84 which fit together with the pulling hooks 45, 47, are fixed to the connector module 13 by steel clips 86, 88. The housing 75 of the connector module 13 and the end wall connector 76 are designed so that they can withstand ^{an ambient pressure of up to 140 kg / cm 2.} The outer dimensions are 6.25 cm x 35 cm.
If two cable sections 20, 20 ' are to be connected to one another, the towing hooks 45 and 47 of the loading components 42, 43 are connected to the associated towing hooks 82, 84 of the short loading components 78, 80 via bolts 90, 92. A connector 62 is associated with each end wall connector 76 at each end of the connector module 13. A plastic cuff 94 with an inner diameter that is slightly larger than the outer diameter of the outer layer 40 is slipped over the end end walls 46. The cuff 94 is fixed to the end walls 46 by steel strips 96, 98. The inside of the cuff 94 can be filled with light kerosene (to achieve buoyancy). A better buoyancy in water can be achieved through syntactic foam.

The connector module 13 is shown in partial cross section in Fig. 3b. Each end of the cylindrical housing 75 of the connector assembly 13 (Fig. 13b) is terminated by a face connector 76 that slides in a recess 100 machined in the end of the housing 75. O-rings 102, 104 form a flow

«) Central sealing around the connector. The bulkhead connector 76 is secured in place by a snap ring 106.

The connector module 13 is shown in cross section along the line 3c-c in FIG. 3c and along the line Zd-d in

b5 F i g. 3d illustrated. The electronics of the transmitter / receiver unit, which is contained in the receiver module 13 (described in detail below), is on three printed circuit boards 108, 110. 112iFie.3a and M \

attached. The three plates that make up the transceiver unit 111 are in the shape of a triangle Prism trained. They are designed so that they can be inserted into the housing 75. Before inserting the inside of the housing 75 is covered with a thin layer of fiberglass (not shown) to allow the electronics is insulated against the metal wall. The connector module 13 is after assembly with mineral oil known type filled, which does not damage the electronic components. This results in good heat conduction and prevents the ingress of water.

In rough weather at sea, the towing vehicle 10 (FIG. 1) is subject to unpredictable accelerations around the pitch, roll and yaw axes. So that such accelerations do not affect the seismic sensor assembly 12 are transmitted, one or more elastic cable sections 16 are between the insertion section 17 and the cable 12 switched on. The elastic cable sections are similar in structure to a active cable section, except that no seismic or auxiliary sensors are included. Ropes made of nylon or other elastic material are used in place of the steel load components. A bundle of cables that corresponds to the bundle of cables 52 of FIG. 2a corresponds to is through the central openings 50 of the end walls 41 led. Sufficient passage is provided in the cable bundle 52 so that the section extends up to can stretch 50% of its relaxed length. In one embodiment, there are two such stretching sections used. A connector component is between the leading end of the first active section and inserted the trailing end of the second trailing elastic portion. A second connector module 13 'is between the trailing end of the insertion cable section 17 and the leading end of the leading Section used

The cable bundle 52 in each cable section 20 contains two sets of conductors. A set of local data conductors, z. B. 58.60 transmits analog signals from the elementary seismic sensor units 21 and the auxiliary sensors within each cable section on the transmitter-receiver unit within an adjacent connector package 13. The local conductors are coaxial cables. The other set of cables are feed-through trunk lines for the transmission of interrogation, command and control Control signals from the ship 10 to each transmitter / receiver 111 in a connector module 13 and to Transmission of data signals from each transceiver unit 111 back to the ship 10. The trunk lines indicate a data transmission connection, an interrogation connection, two command connectors, two test leads and one power transmission line on. With the help of the stretch connections on the connector module 13, the long-distance lines extend over the total length of cable assembly 12.

In a preferred embodiment, the broadband communications link consists of three coaxial cables. Coaxial cables are required to ensure transmission speed of 20 megabits per second (40 MHz for a word that only consists of ONE consists). Three cables are used instead of one for redundancy reasons. If a cable fails, two more are available for operation.

The interrogation connector consists of three redundant twisted-pair transmission lines. Twisted pairs of conductors are permitted for these and all other signal transmission lines because the transmission speed of the interrogation pulses is relatively low, namely in the kHz range. The two command connectors with twisted cable pairs carry the control signals. The test control lines are twisted wire pairs, ^r , through which a test signal and a test control pulse are transmitted.

The power transmission line consists of two twisted pairs of a wire connected in parallel are. This line is used to generate alternating current energy

ίο transmitted to the energy feeds for the Sendcr-receiver units which are present in each of the connector modules 13.

A block diagram of a transceiver unit 111 mounted on printed circuit boards 108, 110, 112 (Fig. 3d) of a connector module Ϊ3 is attached, is in F i g. 5 shown. The essential components are a repeater network 114, a query network 116, a connection network 118, preamplifier 120, a multiplexer 122, amplification determining amplifier 124, an analog-to-digital converter (digital display device) 126, a code register and a code converter 128, an error detector 130, a control network 132, an energy supply source 134, a driver 136 of a test circuit and a test control relay 138. Die Transceiver circuit elements are discussed in detail below. The functions of the transmitter-receiver unit 111 are shown in block form in FIG. 5 for a better understanding of the operation shown schematically.

The repeater network 114 transmits a local, self-clocking, phase-coded data word to the central station 2 (FIG. 1) via the data transmission link Di, D 2, D 3 and then receives, regenerates and transmits self-clocking, phase-coded data words from the downwardly connected data words Transmitter-receiver units. These functions are initiated and completed as a function of a first interrogation pulse before a second interrogation pulse arrives. On command or in the event of a power failure in a transmitter-receiver unit, the receiver can be bypassed in a shunt, as will be explained below.

The interrogation network 116 receives, buffers and transmits interrogation pulses over the triple redundant interrogation connector / PI, IP2, IP3. In this unit, the interrogation pulse is identified by a pulse width identification circuit as it is either a wide pulse 51 or a narrow pulse S2 . The S 1 pulse is 1500 nanoseconds wide; the S2 pulse is 600 nanoseconds wide. The interrogation network 116 has a delay line in series with the interrogation connector. The delay is 600 nanoseconds. The delay line is tapped so that small adjustments can be made to compensate for small differences in signal propagation times through the interrogation connector.

The command network 118 accepts the two command signals DATA (make data effective) and DA-

bo TA BYPASS on, buffers and transmits it to the downlinked transmitters / receivers. The simultaneous arrival of a 51 interrogation pulse and a DAR > 4-i? Y7M5S pulse at a selected transceiver unit causes phase-encoded words to be bypassed around the corresponding repeater network 114, as will be described further below . With DA TEN a pulse is referred to, the width of which is a multiple of

Vcr / .delay / .eil is set on in the query network 116 is adjustable. The Sendcr-Receiver Units in one or more juxtaposed cable sections only through the simultaneous Presence of a £> / 4T £ W pulse and one 51 query pulse activated, both of which are different .Signal pulses are.

The query network 116, the command network 118 and repeater network 114 are power failure shunts which are operated by relays as described below. in the In the event of a power failure, the relays are switched ineffective, so that incoming phase-coded Words and query and command pulses are directed around the defective transmitter / receiver.

Analog data are obtained from the elementary seismic Sensor units 21 via local coaxial cables 58, 60 through amplifiers 120 and filters to the inputs of the multiplexer 122 are transmitted. When responding to a 51 pulse passed through the interrogation network 116 is picked up and displayed, the control network 132 sets the multiplexer 122 to channel No. 0. Depending on the leading edges of a series of S2 pulses, the multiplexer is via a normal scan cycle sequentially so that it polls the input channels one by one. In this embodiment there are 14 input channels. Channel no. 0 is a blind or pseudo channel. Analog seismic data signals are transmitted on channels 1 to 10. Analog signals off Auxiliary sensors are transmitted through channels 11 to 13.

When the multiplexer 122 is reset to channel # 0, certain so-called organizational Operations and test functions performed: The gain determining amplifiers 124 are set to gain 1, while the DC deviation at the multiplexer and at the Amplifier inputs is automatically compensated. At this point in time, there is a fault indication sound, which is described below, a warning sign when one or more of the three redundant data transmission lines are defective.

Since each of the channels 1 to 13 is queried, the sampled analog data signal is also transmitted via the Gain determining amplifier 124 is raised. As is known, seismic signals have one wide dynamic range of up to 120 db (1 million: 1). Signal gain conditioning includes compressing the dynamic range of seismic signals to the range within the boundaries of the Anaiog-Digiiai-Urriwandlefs too close. That accordingly The signal adjusted to the gain factor is converted into a binary number by the analog-to-digital converter 126 that forms the sign and mantissa parts of a number with a floating point. The reinforcement states of the gain determining amplifier 124 are coded as a four-bit code. This four-bit code is combined in terms of the mantissa part in the output register 128 so that a Floating point number with 10 to 16 bit resolution results. This floating point number represents the amplitude level of the Seismic data signal at the time of the sample or test. Including four additional bits of a parity bit can be added to the data word as a preamble, so that a correct Identification of the beginning of the phase-coded words is possible

The 20 hiis which represent the data word are encoded in any suitable, self-clocking code and are transmitted in the return-to-zero mode (RZ) via a broadband telecommunication connection in direct communication.

■> transfer digital data transfer mode. In one embodiment, a self-clocking code, e.g. B. the code known as two-phase M is used. An example of a coded data word is shown in FIG. Self-clocking codes like that

ίο shown here are in "The Interface Handbook" by Kenneth M. True, published by Fairchild Instruments Co., 464 Ellis Street Mountain View, California, on pages 4 to 18. In this publication, circuits that implement such codes are discussed. The lack of data is represented by a logic level of zero 50 nanoseconds before the first data bit, the logic level drops to -5 V, so that the first data bit is a positive going Must be impulse. Each data bit takes up a setting time of 50 nanoseconds. A binary "1" becomes represented by a polarity reversal in the middle of a setting time of 50 nanoseconds, while a binary "0" is represented by no polarity reversal. Consecutive binary zeros are through consecutively 50 nanosecond polarity changes occurring at the actuating time limits are shown. Since 20 data bits are present, a phase-coded word takes up a time slot of 1000 nanoseconds, i.e. one milliunstel Second one. At the end of a phase encoded word, the logic level drops to -5 V for 75 nanoseconds and then goes to zero. The logic circuit in the repeater network 114 always looks for one positive outgoing pulse within an interval of any two digit times. If there is no such impulse

js is set, the logic sets the end of a data word fixed.

The maximum phase change frequency of the phase encoded words is 40MHz (for all ONE). Because of the fast rise time on the leading edge of the pulses, the bandwidth of the communications link must be at least 100 MHz.

The inputs to multiplexer 122 are AC coupled through capacitors 123. The multiplexer output is connected to the amplifier 124 via the series resistor 140 and the buffer amplifier 142 coupled to the gain factor 1. The capacitors 123 and the series resistor 140 form together with the multiplexer 122 a high-pass commutation AC filter. The cutoff frequency of the filter is

f ~ [\ / 2 (2 RCJ \ (D / T),

where D is the channel switch-on time and Γ the channel switch-off time is. The filter is described in detail below in connection with FIGS. 15 and 16.

The operation of gain conditioning amplifier 124 in conjunction with the analog-to-digital converter 126 and the output register 128 to form a data word with a floating point will be discussed further below in connection with FIGS. 39 to 42 described.

In a typical cycle of operation, all 14 analog channels of each transceiver 111 queried within a scanning cycle A new scanning cycle is scanned at a desired scanning speed, z. B. once every half a millisecond or a millisecond, initiated at a query speed of one Millisecond the 14 channels of each transmitter /

The recipient is queried at intervals of 71.4 μβες. the Completion of a scanning cycle requires that the interrogation device in the control unit 4 of the common central station 2 of the ship 10 a 51 pulse and transmits thirteen 52 pulses per millisecond.

11 shows the time sequence of the interrogation signals, namely the 51 and S2 pulses within a sampling cycle of one millisecond duration. When a 51 interrogation pulse is passed down the interrogation link IPi, IP2,

lernctzwerk 114 in the connector module 113A, 1160.3 nsec later than the leading edge of the phase-coded word from the connector module 13, 4 das Repeater network 114 has left. This enables a phase-coded word separation of 160.3 nsec duration are provided.

A two-stage run-time sequence / channel sequence multiplex system is explained below. The phase-coded words that are made up of consecutive of the 50

IP3 advances in the cable arrangement 12 to the transmitter / receiver units in the connector modules gereinheiten U1 (FIG. 5), those that are transferred are reset to channel 0 depending on the speaking multiplexer. At the transit time of the interrogation pulse between the central one, a data word is sorted by the control network station and the corresponding transmitter-receiver unit 132 from the output register and code converter. Phase-coded words from the four-128 clocked via the repeater network 114 into the data is ten channels within each corresponding transmitter transmission connection Dl, D 2, D 3. The receiving units are ordered depending on the channel selection sequence during the scan cycle.

The DA TEN input from the central station to the command network 118 in Figure 5 controls the operation

view neighboring transceiver links 20 and 20 of the system in the manner indicated above. The delay time control set in the query network for the transmission of a DATA pulse

phase-coded words are delay-multiplexed in the data connection due to the impressed delay of the interrogation pulse between

processed. After 71.4 U> sec, the first 52 pulse transfer. The multiplexers in the transceiver units 111 are successively on channel no

allows either all or a portion of the seismic cable assembly to be used of it, for example the front half of the Kabclab

switched on when the 52 pulse intersected each transmitter 25. As mentioned above, it may be desirable to have the

Receiving unit reached. Thereupon, phase-coded words are again clocked into the data connection by each transmitter / receiver unit in a chronological order 52 pulses are transmitted until all channels in all transceiver units have been polled.

The above-described sequence is shown in the timing diagram of FIG. 12 shown. The interrogation pulses (IP) run outwards, i.e. downwards with respect to the connection,

elementary seismic sensor units in the half of the cable near the ship with a sampling speed immediately following the generation of a seismic pressure pulse and then interrogate the signals from the entire cable at a different speed. For these functions, DATA pulses are used according to the length and timing. The following description describes the required

Multiplexer 122 of the transmitter / receiver unit on channel no. 1. After passing through the delay line, the 52 pulse leaves the connector module \ ZA

the transmitter-receiver unit in the connector module 13B is 60 m. Assuming a propagation speed of 1305 nsec per foot in the interrogation connection

from right to left (the time base increases to the right 35 timing and length of the DATENAmpuke all too) from the central station 2 to the transmitter-receiver explained, so that any number of sender units in the 50 connector modules 13/4, 13ß, the -Receiver units selectively activated 13C etc. “in that order. In the upper three dar- can be.

12 positions therefore takes the time from before examining the timing diagrams in detail

left to right too. If a 52-pulse arrives, for example, it appears expedient to view the entire data sense at the connector component 13A and switch to the detection scheme and the time frame

which the data generated by each of the 500 elementary seismic sensor units from the cable be transmitted. First of all, it should be noted that

600 nsec later. The distance between the transmitter 45 of each of the 50 cable sections ten elementary seismi-receiver unit in the connector module 13 / \ and see sensor units along its length as well as one assigned transmitter-receiver unit, which processes the data from these ten sensor units. on Command from the control unit 4 in the central station 2

Connection piece IPi, IPI, IP3 with twisted pairs, so that on board the ship (Fig. 1) the S2-! S! Pulse phaser. Encoded words from 256.8 nsec later a ». The total delay between the last channel of each of the 50 cable sections of the modules 13/4 and 13S is 856.8 nsec. from the cable one after the other via the individual data

As soon as the leading edge of the S 2 pulse for the card connection D 1, D 2, D 3 (which consist of three redundant channels No. 1 through the transmitter / receiver unit in the connection), the module 13A has been detected is, a phase coded word is transmitted after receipt of a narrow 52-pulse from the register 128 in the data transmission the transmitter-receiver unit 111, which is clocked for each of the 50 Kagungsverbindungen D 1, D2, D3 The data flow is assigned to sections, the information des Ka takes place from left to right (the time base increases after line no. 1 from each cable section sequentially, left), ie upwards with respect to the connection ω Then, following the reception of another against the central station. As soon as the 52-pulse at S2-Inipulscs the information of the channel no. 2 from each connector module 130 856.8 nsec later arrives, to which the 50 cable segment is given, etc. the data word for the connector module 13ß with regard to the time control occurs each Cycle for

Clocked out in a similar way. The signal speed is checked for 1 msec of the signal that is present on all 50 channels in the coaxial cable that connects the data. This cycle, represented as the setting, is 1342 nsec per foot. The load cycle is therefore defined and corresponds to the duration between the leading edge of the phase-coded word successive 51-pulses, with 5 I-pulses 13 following each other from the connector module 13 on the winder before the next

Sl pulse is generated. The transmission of an individual bit of a phase-coded word takes only 50 nsec. each phase-coded word is represented by 20 bits, for example, and each phase-coded word is transmitted in about 1000 nsec. Since each ^r , test interval has a duration of 1 msec (1000 μββΰ), there is enough time to transmit data signals from the 500 seismic channels in time sequence over the cable during a sampling cycle.

The activation of one or more transmitter / receiver units requires the simultaneous presence of an SI pulse and a D / 47TA / (data control) pulse, as will be explained in connection with FIG. At the leading ends of each section are connector modules i ^r > 13/4-G, each of which contains a separate transceiver unit. For example, it is assumed that it is desired to activate only the three successive transceiver units in the connector modules 13C, 13D and 13E, but not any others. The circuit for carrying out this function is explained in detail further below in connection with FIGS. 43 to 48, but a brief description is given here for a better understanding of the embodiment shown.

An S! Pulse is transmitted from the central station 2 via the interrogation connector to each connector module 13 in turn. The moment of arrival of the signal pulse 51 at module 13/4 is t = 0, the arrival time in module 13ß is t = 856.8 nsec, the arrival time of signal pulse S1 at module 13C is Z = 1713.6 nsec, etc. The six timing control lines in Fig. 13, labeled IPA through IPF represent the locations of the same SI pulse with respect to connector modules 13/4-F, each containing separate transceivers, at the end of each 856.8 nsec interrogation pulse travel time interval. Some time after an SI pulse has been transmitted, a D / 4r £ 7V pulse is transmitted over the connector (Fig. 5). The waveform walking speeds in the twisted wire pairs containing the interrogation and command links are the same. However, because of the 600 nsec delay line in each transceiver unit connected to the interrogation network 116, the effective 51 pulse rate is lower than the command pulse rate because there are no delay lines in the command connector. Correspondingly, a DATA \ mpu \ s takes about 600 nsec, but due to the width of the DA TEN pulse, it is still available to activate the transmitter / receiver unit in the connector module 13D. At the module 13 £ the trailing edge of the DA- TF / V pulse has not yet passed the / P pulse 51, although the leading edge of the D / 4T £ A / pulse leads the pulse 51 by 1200 nsec. Thus, the transmitter-receiver unit is activated in the connector module 13 £. Finally, by the time the 5 1 pulse arrives at the unit in connector module 13F, the trailing edge of the D / 4TEW pulse leads the S 1 pulse. The transceiver unit in the connector module 13F and all subsequent transceiver units are therefore not activated. All transceiver units that are activated by the coincidence of 51 and D / 4r £ 7V pulses remain activated for a full scan cycle so that they respond to all subsequent incoming 52 pulses. The width of Weines DA TEN impulse is

whereby

DLY

- 1) * DLY] + df

Number of transmitter-receiver units to be activated, artificial delay and a small increase in time of arbitrary length, around small delay time differences to enable are.

In the example according to Fig.
7i7V impulses

13 is the width of the DA

j5 [(3 - 1) x 600] + 300 = 1500 nsec.

The initial running time ED that is given to the DATEN pulse is

/ "" = M ■ DLY,

where M is the number of transmitter-receiver units, which are skipped between the central control station and the first active transceiver unit.

As discussed above, a DA TA-BA YPASS pulse which coincides with an SI pulse is used to route data around a defective transceiver unit. The delay BD that

which has been delayed by 1200 nsec in relation to a corresponding 50 to the DA 7/4-ßV7MSS pulse relative to an assigned // M pulse, the S 1 pulse is applied to the nth S 1 pulse
third transmitter / receiver unit in the connector component

13Cauf. The six timing lines that start with DA TEN- BD = K ■ DLY,

AF indicate the position of a DATA

Pulse in relation to the S1 pulse at the end of a 55 where K is the number of transmitter-receiver units every 856.8 nsec interrogation pulse transit time in- between the central station and the defective interval. th transmitter-receiver unit.

When an S 1 pulse is sent to the transmitter-receiver input terminal. 5, the data and query connections exist

means arrives in the connector module 13/1, this has no fertilizers that represent a part of the cable bundle 52, effect on the module 13Λ because the DATA-lmpuh eo consists of three parallel lines. If one of the leium lags 1200 nsec. At the transceiver unit obligations is defective, the other two are Verim connector block 13S leads the DATA \ mpu \ s addition. By majority vote, two good lines are selected after 600 nsec, so that no effects are selected on module 135. A majority voting circuit 131 occurs The DATA pulse intercepts the SI pulse is coupled to the input conductors of the repeater network of the transceiver unit in connector component 13C 65 114 and another such circuit (not off, so that the transceiver unit is shown in the connector) is assigned to the query network 116 module 13C is activated. Circuit 131 from FIG. 1 hurries at module 13D. 5 is shown in detail in FIG. 6 leading edge of the D / 4 TSV pulse shown the SI pulse and consists of AND gates 136, 138, 140

45 46 lbs

and an OR gate 1 * 2. Its logical "1", which result in stretching, must be corrected. |

is present on two of the diäi data conductors at the same time. As is known in seismics, the individual Hy- |

a logical "I" at the output of the OR drophone seldom generates identical sensitivity. An off

Güed's 142nd deviation of ± 25% is not uncommon. It is there-

An error indicator circuit 130 is most desirable for calibrating the hydrophones. In addition

ity selection circuit in the repeater network 114 is coupled an analog test signal of known amplitude to the

pelt and produces a signal in the event that at least test control circuit 136 via test signal line 162

one of the data lines Di, D 2 or D 3 is defective transmitted (FIG. 5). The test signal frequency is both

The circuit (Fig.6) consists of a NAND gate for example 15.625 Hz. A test control signal is via

144, a diode 146, a storage capacitor 148 io the test control line 163 to the test control relay 138 - ■

and a bias resistor 150. A negative transmitted which a switch contact arm 164 of Kon- k

Voltage is switched over to fault display line 152, single clock 165 to contact 166 . Now a test %

sets to keep it slightly negative when no output signal is given up to the elementary seismic I.

from the NAND gate 144 is present If one of the sensor units 21, each via a resistor |

Lines Dl, D 2, D 3 is ineffective, the NAND-15 stand 168 is to be energized. A normal multiplexer sampling ₍ f

Member 144 in passage connected During a /.yklus is introduced to the output from each transmitter H

normal sampling cycle, phase-coded signals sorcinhcit 21 flow to central station 2 in ship IO to j |

transmitted at a frequency of 40 MHz by the majority. The amplitude of the output signal of each ä

selection circuit and in the NAND gate 144. that with the monitoring unit is compared with the test signal amplitude

Inputs of the repeater network 114 are connected to chcn in order to set a calibration factor for each sensor unit

is As long as all three lines are in good working order, come on. The sensor units are calibrated

NAND gate 144 has no output signal. If any line point to the seismic data;

but a line is defective, there is a 40 MHz signal on the nich! to be recorded. ; _; ..

The output of the NAND gate 144 is present. The signal The test signal is used to ensure an exact measurement

is rectified by diode 146 . The result of the sensitivities of all sensor units in the

The rectified voltage is passed through the entire seismic sensor cable arrangement 12 in the capacitor.

148 and apply a positive error voltage which can be up to 2 miles long. Over a '

error indication line 152 is generated. During such distance, due to the ohmic span

the period during which the multiplexer 122, on the voltage drop, the test signal at the expiring end of the

Channel No. 0 is reset, the switch arm 154, 30 of the cable is severely weakened when the test signal control

which is connected in parallel to the test signal line between the amplifier 124 and the analog circuitry 136

gital converter is arranged (Fig. 5), closed by the contact. There will therefore be a resistance of 167 in

156 switched to contact 160 and enables series with test signal line 162 in each transmitter

that the analog-to-digital converter 126 placed the span receiver unit The inputs of the test signal

voltage level, the control circuit on the incorrect cranze line 152 are 35 parallel to the series counter-

action is checked in F i g. 5 is switched to stand 167 for the sake of simplicity; since all resistances are the same

mechanical switch 154 shown, in practice have a resistance value, all test signal control

however, a Schottky junction transistor can be used as input voltages identical to crcircuits. On the-

Binary digit speed operating switches in a different manner becomes one for each transmitter / receiver unit

be turned. 40 test signal of constant amplitude guaranteed.

Sea streamer cable of the type described above is provided in each transmitter / receiver unit 111 with an end-to-end supply source 134 for stretching by up to 1% when towing. The necessary supply. With a cable of 3000 m length, the total extension of the ship in the connector building is in the order of 30 m. Stone 13 via a pair of twisted conductors 170,172 . Each energy supply source has a current transmission distance offset within each cable section. formator and a shunt regulator. At a stretch of 30 m, the sensor unit primary windings are connected in series in the corresponding Senten at the leading end of the cable arrangement 12 around the receiver units in the connector modules 13 with respect to the sensor units. By crossing the lines in the outgoing end of the cable arrangement, 50 170, 172 in each cable section 20 is shifted alternately. When assembling a larger group of each transformer on an opposite side of the piercing from a number of elementary sensor inputs as shown in Fig. 4, it is therefore necessary to know the exact sensor unit. If the distance won't keep exactly. Since the energy supply sources are known in series, the effectiveness of the composite 55 is switched, the voltage drop along the Katen grouping is considerably worsened. The reference arrangement 12 between the ship 10 and the dependence between the cable extension and the towing section 18 on the number of connector construction voltages is known. Correspondingly, stones 13 which are connected to one another are expedient. In the case of a strain gauge 11 (Fig. 1) known cable arrangement with 50 sections of the type with the load components between the 60 voltage drop of the order of 400 to running elastic cable section 16 and the first 500 V. The energy is at a frequency of 2000 Hz active cable section 20 connected. The output from with an average current strength of 4 A over the strain gauge II will bear the Kingang one. This frequency is essentially supplied via the nor auxiliary channel, the seismic frequencies in the transmitter / receiver and does not affect this in the connector component 13 'at the leading end of the b5. The first elastic cable section is arranged in the Spcisequelle 134. From currentcncrgie from the power line rectified to the knowledge of the drag voltage, faulty and in ± 15 V and + 5 V for use in the logiler in the sensor unit offshore. which can be seen from the cable circuits in the transmitter-receiver units

converted In the event of damage, e.g. B. an open circuit in a transmitter / receiver unit the voltage on the primary winding of the power transformer increases to a high value. One Protection triac rectifier bridge circuit known Design switches the primary winding short if the voltage rises above a predetermined value If the energy supply source fails, the reliable bypass relays (not shown) in the repeater network 114, query network 116 and command network 118 drop out, so that the command pulses and the phase-coded data words can skip the defective module.

As previously described, the multiplexer 122 has fourteen inputs, of which channels # 11 through 13 can be used to transfer data from the auxiliary sensors, as explained below. The pressure transducer 60. which is described in connection with FIG. 2a has been mentioned and is described in detail below, is a known per se in seismics Converter. Its function will be briefly explained below. As in Fig. 7a, the transducer a tube spring 174. A soft iron pole piece 176 is connected to the movable end of the spring 174. The pole piece 176 moves longitudinally in a coil 178, which is attached to the fixed end of the spring 174 via a support arm 18l] i. An oscillator that contains an LC oscillating circuit is in a housing 182 added. The coil 178 is the inductive part of the resonant circuit, effected in a fluid a change in pressure against the tube spring 174 that the pole piece 176 moves in the coil 178 thereby the inductance and thus the frequency of the oscillator is changed. The output signal of the pressure transducer 64 is thus a frequency-modulated signal, the frequency of which is related to the surrounding fluid pressure. The signal is based on a coaxial cable Channel No. 11 of the multiplexer 122 transmitted as the F i g. 7b shows

FIG. 7 b illustrates a leak indicator device 186 which indicates the presence of salt water within the outer skin 411 of a cable section 20. The leak detector 186 consists of two Wires 66, 68 poorly insulated by porous plastic material. The porous coating prevents physical contact between the wires, but allows the water to make fluid contact. The two wires 66, 68 extend the length of the cable section 20 Wire 66 is connected to oscillator output 184 of pressure transducer 64. The other wire 68 is with the auxiliary input channel no. 12 of the multiplexer 122 connected. As long as keto water penetrates into the interior of the cable section 20 is the leak detection channel no signal given. When water penetrates the cable section, a conductive path is created between the two wires 66 and 68 and an amplitude modulated signal appears on the auxiliary leak detection channel. The amplitude of the signal is proportional to the resistance of the leakage path.

A display device 72 for detecting and interrupting a surface wave is connected to the auxiliary input channel No. 13. This display device 72 is a special hydrophone which is used to detect an acoustic wave emitted directly by the Sound source arrives along a path near the surface of the water. Although all active cable sections are identical and are interchangeable, it is necessary to provide an impedance matching termination to connect the data command and interrogation signal lines, i.e. the Complete transmission links at the last section to prevent unwanted reflections will. Furthermore, the twisted, series-connected energy, test and test control wire pairs must be provided with a feedback circuit. Is accordingly a terminating section 18 is provided at the trailing end of the last cable section 20.

The structure of the terminating section is shown as cable section 20 in FIG. 8a. The outer layer 40 is shown with the end end wall 46 upper steel strips 54,56 set. Cable bundle 52 and connector 186 extend beyond the end end wall 46 together with strain relief components 42, 43 and draw hooks 45, 47. A corner swivel connector 188 is provided at the trailing end of the terminating section 18. An end to three short relief components 190,192 (the third is μ not shown) is embedded in the plug body Draw hook 194,196. which cooperate with draw hooks 45,47 are fixed via bolts 198,200.

The terminating module 202 is attached to the relief components 190,192 via a steel band 204 Conductors contained in a cable bundle 52 are electrically connected to the terminating module 202 via a plug 186 and associated plug 187 connected. A plastic cuff 206 is over the plug 188 and the End end wall 46 of the last active section 20 striped The cuff is made of steel strips 206,210,212, 214 set in place.

The space inside the cuff 206 is filled with light kerosene to achieve buoyancy.

The electrical connections within the termination module 202 are shown in FIG. Coaxial data transmission lines D1, D 2 and D 3 shown in FIG. 8b are terminated via resistors 216 with 50 ohms, V ₄ watts. The twisted wire pairs for the lines IP1, IP2, IP3 of the interrogation connection and the command wire for the signals DATEN and DATA-BYPASS are terminated with resistors 218 of 130 ohms, V ₄ WaU. Power, test signal and test control lines are short-circuited by jumper wires 220. The feed cable section 17 is coupled to the leading end of the elastic section 16 via a transmitter / receiver unit in the connector module 13 '. The other end of the feed cable section 17 is attached to the ship 10, which creates the possibility of towing the cable section 12 and also of establishing a connection to the central station 2. The feed cable section 17 is shown in cross section in FIG. It consists of a central loading component 230 in the form of a non-rotating steel cable with a diameter of 0.9375 cm. The loading component 230 is sheathed with neoprene or other plastic 232. The current conductors that form the cable bundle 52 in the active cable section are wound in a spiral shape around the sheathed load component 230. The conductors themselves are enclosed in a plastic sheath 234. bo The lines are in F i g. 9 as coaxial data lines 236, auxiliary lines 238 with double twisted wire pair, command lines 240 with twisted wire pair and coaxial local data lines 242. Since the feed cable section 17 can be up to 180 m long b5, the data lines 236 are RG / 59 U coaxial cables, which prevent signal degradation. The local data lines 242 extend from the ship 10 to the connector module 13 ', where they are connected to the

49 50

Inputs are connected. The local data lines are provided with nem (') so that the

242 are used to feed signals that are visible from close existing correspondence,

special sensors 222 arranged in the ship 10. In FIG

(F »8-1) can be obtained. single common shunt resistor 315 '

To explain the filter that is used in the illustrated s on the output line of the multiplexer 122 Embodiment is used, an individual shunt resistor 315 is used below for each

Referring to Fig. 14, in which a simplified is shown the channel when the multiplexer 122 is over

Representation of the digital-to-analog conversion system its channel selection cycle, i. H. Scanning cycle continued

is shown, in which the multiplexer 122 is connected to the input, the capacitor 123 'represents. the in series

channels Ci, C ₂ , C with a variety of signal sources, io with each channel selected by the multiplexer, e.g. Ci, C ₂

e.g. seismic sensors 21 is connected to the on etc. is connected to the common

gangskanä'.e are all with the multiplexer output shunt resistor 315 'the desired AC filter

Multiple lines 312 via coupling capacitors for this channel.

123, resistors 315 and switches 316 connected. As the circuit of FIG. 15 was tested, the resistor 315 in connection with its 15 turned out experimentally (which later theoretically became a high-pass AC filter for a capacitor) that the capacitance C is determined Switches 316 are fast field effect transistors through: stor switch of a known type

The output of multiplexer trunk 312 is C = [1 / (2a7Vo)] [0/7] (D)

with the non-inverted input of a buffer amplifier 20

kers 320 is connected to the gain 1, where D is the dwell time, ie the length of time that each

an operational amplifier, e.g. amplifier 142 after switch 3I6 is closed, and T the channel switch-off

F i g. 5, with a high input impedance can be. time is d. H. the length of time that each switch 316 is open The output of the buffer amplifier 320 is net is The dwell time D is a function of the number Connected test and hold circuit 322, which has a Ne-2; of analog channels and the total time required

shunt capacitor 324 and a series switch 326 Hch is to scan all of these channels. For a mul-

having. The output of circuit 322 is a liplextr with 16 channels and a sampling duration of

binary amplifier 124 with variable gain 1000 usec, the maximum dwell time D is 62.5 usec

degree of efficiency, as shown in FIG. 5 is shown and in connection per channel and the channel switch-off duration T937.5 usec.

dation with the F i g. 39 to 42 described below 30 The dwell time D can be adjusted with the aid of the dwell time

is coupled to control circuit 360 of FIG. 16 can be changed. the

The state controller that controls the dwell setting circuit 360 may be a monostable

132 is to be with the switches 316,326 via a control circuit. The pulse width setting is made with

Trunk 341 which achieves a variety of means of RC feedback known in the art Has control lines. The control unit 132 switches 35 via a Multiplcxcr sampling cycle, the

set the multiplexer 122 in sequential order to the control desired dwell time to the same value

input channels Q to C _n , which are thus one after the other

during a multiplexer sampling cycle in the above equation (D) can thus be described as follows

described manner with the output multiple line:

■ _fV 312 can be connected. The control unit 132 also controls 40

ner the mode of operation of the binary amplifier system 124 / i, = [\ l (2xRCJ \ [D / T \ (E) [S via the control lines 350.

If the amplifier system 124 is coupled to the analog-digi- At constant values for R, C, T can the limit frequency converter 126, which converts the checked frequency of the filter into corresponding digital signals by changing the dwell time will. In the case of the numerical example given above, in the circuit according to FIG. 14, each RC example has the maximum dwell time for a pass filter is a series capacitor 123 and a sampling time of 1 msec 62.5 μ5βΰ. The shortest dwell resistance 315, which is connected to earth, duration is determined by the detection time of the test and Hal-. ; on. Each of these circuits has 322 'intended for use in seismics. For example, the high-pass filter has a lower cut-off frequency / Ό in the size 50 detection time 8 μβεα The dwell time setting switch order of 1 Hz, although other cut-off frequencies 160 must be programmed in such a way that an out-quenzen is possible. Selectable dwell time range is obtained, which is based on the capacitance Cist by the following equation, for example, from a minimum dwell time of: Resistance R and the limit frequency / 0: 8 μβοο up to a maximum dwell time, which is determined by ί 55 the sampling time, which 62.5 μββϋ in the λ C- \ l (2R & h) (C) example above is sufficient. Thus the '['.; Cutoff frequency of the filter to a desired value K ^ For practical design reasons, R must be set over a range of almost 8: 1. | f, 'be relatively small, namely on the order of The way of using the improved, VX of 10,000 ohms. Thus, for / ö = 1 Hz, the value 60 is multiplexer-commutated RC filters in the se- * "■ of C = 16 microfarads. Such large capacitors mix data processing equipment is shown in FIG Since Figures 14 and 1b are very similar, the B / C filters according to Figure 14 are not only expensive, but the description of Figure 16 is limited to the details against miniaturization. Differences between the two representations. | ^; - The description of the filter arrangements according to the ω The most important feature of the utilization of the Kabclpi "Fig. . Chen parts either with identical designations as for seismic data recording devices . in Fig. 14 or with identical reference numerals and is applied, the combination with a common

men shunt resistor that is applied to the output of the multiplexer. It is not just the number of shunt resistors, but the size of the required capacitors 123 'has also been reduced by a factor of 15: 1 in the case of 16 input channels. In addition, the Cutoff frequency can be set by changing the dwell time over a range of almost 8: 1.

F i g. Figure 16 shows that it is convenient to use a low impedance operational amplifier 320 '. Of the Series resistor 315 ″, which corresponds to resistor 140 in FIG. 5, is the input resistance to the inverting input of amplifier 320 '. The non-inverting input to amplifier 320 'is ground Since both inputs must have the same potential, the connection point 333 is practically on Earth potential. Therefore the filter of Fig. 16 is that Equivalent to the filter according to FIG. 15th

Accordingly, the operational amplifier 320 'with low input impedance, in which the common resistor 315 "of the filter is used as the input resistor, is the more economical filter circuit Amplifier 320 is given a relatively high input impedance (FIG. 14).

It has been found that the use of a common resistor 315 "(or 140 in FIG. 5), the successively connected to capacitors 123 by switches 316, a considerable saving in the number of resistors and required in the space occupied by the resistors and capacitors

At this point in the description of the seismic installation, some general explanations appear necessary, and reference is made to FIG. 17, which shows a block diagram of the general structure of this multi-channel seismic device, which has a central station 2 and a multiplicity of transmitter / receiver units 11 1a to 111 π which are arranged remotely from the central station 2. The transmitter-receiver units lilac to 11 In are connected in series with the central station 2 via broadband data transmission links 1014a to 1014n and interrogation links 1016a to 1016n which correspond to and represent the channels or links Dl, D2, D3 and IPl, IP2, IP3, these channels being arranged in the manner described above within a section of the seismic streamer cable.

Each transceiver unit 111 is shown as having the interrogation network 116 and a repeater network 114. Each repeater network 114 contains a number of input channels 1022, 1022 ', 1022 ". Three such channels are shown in FIG. 17 for the sake of simplicity, but in practice fourteen or more such channels can be used, as stated above. Elementals seismic sensor units 21, 2Γ, 22 "are coupled to input channels 1022, 1022 ', 1022" and are up to ten or more such sensor units are provided in each cable section, so that 50 or more such sections 500 or more individual elementary Seismic .Sensor units contain, each of which represents a separate information channel.

In Fig. 18 shows a transmitter-receiver unit in a detailed representation; each analog channel is 1022 connected to a separate preamplifier and an »ALI-AS« filter 1036, which is connected to an input terminal The multiplexer 122 has input connections C1, C2, C3, C4, CS (five channels are shown, but fourteen channels are shown)

5 or more channels are used), one for each channel 1022. The channel CO is the test channel. The channel CO contains a capacitor 1043, the is placed on earth. The output of the multiplexer is via the common series resistor 140 with the

ίο operational amplifier 142 connected. The capacitors 123, the multiplexer 122 and the common series resistor 140 form the above-described, multiplexer-commutated high-pass AC filter for each channel.

The output of the amplifier 142 is applied to the test and hold circuit 1044, which has a Serienschalt.er 1045 and a shunt capacitor 1046, which corresponds to the arrangement described above is connected to another test and hold circuit 1050 through a buffer amplifier 1048. The buffer amplifier 1048 separates the two circuits 1044 and 1050. The test and hold circuit 1050 includes a series capacitor 1051 and a shunt circuit ter 1052, which is connected to earth. The exit of circuit 1050 is coupled to binary amplification system 124. The test channel 1041, i.e. H. the channel CO, in connection with the test and hold circuit 1050, is a new work to compensate for equal current or zero point deviations, which in detail in connection with F i g. 37 explained below will. The binary variable gain amplifier 124 has four double gain amplifier stages, namely the amplifiers 124a, 1246, 124c and 124rf that are cascaded are. Each amplifier normally has a low gain condition, e.g. B. the gain 1. The feedback can be adjusted be that a discrete high gain state grads is obtained for each amplifier, and it can done through switches 1055a, 1055b, 1055c and 1055rf. The binary changeable amplifier arrangement 124 will be described in detail below in connection with FIGS. 39 to 42 described.

The output of the amplifier arrangement 124 is applied to the analog-to-digital converter 126. This Analog-to-digital converter 126 takes a gain conditioned analog signal sample and converts it into a binary number in a direction-dependent one gen pulse code (Non-Return-to-Zero-Code = NRZ- Code). The output of converter 126 is sent to the temporary value memory register and code converter 128 fed. The code converter 128 converts the binary number of the directional pulse code into one converts the self-clocking, phase-encoded pulse code that can be applied to the transmission link 1014 via the line 1057, the regenerator 1060 and the transmitter 1066. The data transmission connection 1014 schematically represents the data connection oil, D2,

bo D 3, which above with F i g. 5 is described.

The timing functions of the various networks in each transceiver unit 111 are performed controlled by the aforementioned control unit 132, which sends an interrogation pulse from the interrogation network 116

ti? in series with the interrogation connection 1016, which was shown schematically by connection IPX, IP2, IP3 above. A master controller 1019 in the central station 2 transmits over the link

1016 the broad SI pulse, to which a number of narrow S2 pulses within each sampling cycle. A sampling cycle is required for the 13 input channels shown and the one test channel the transmission of a S1 pulse followed by 13 S2 pulses.

The interrogation network 116 consists of a pulse width detector 1031 and a delay line 1029. If the pulse width detector 1031 indicates a broad 51 pulse, it outputs a control SYNC pulse over the line 1035 to the control unit 132, which the Resets multiplexer 122 to channel 0, which causes a possible DC operating point shift eliminated and the transmission of a phase-coded data word from the last channel of the previous one Scanning is initiated. When the pulse detector 1031 displays a narrow 52 pulse, it sends one But pulse the line 1033 so that the control unit 132 switches the multiplexer 122 to the next channel and transfers the data from the previous scan. The S1 and 52 pulses exceed the delay line 1029 continues and are delayed enough that there is a separation between the end of a local data word as it is received by the transceiver unit 11 la, and the beginning of the data word that comes from the next, downwardly connected transceiver unit, e.g. B. the Unity Uli »arrives, is guaranteed. This gap between the data words of neighboring transceiver units is necessary in order to have a correct distinction.

As explained above, a phase-coded data word is 10000 nsec long. Lines 1016a and 1014a (Fig. 17) are each 60m long and the running time is about this line is 1.6 nsec / foot (533 nsec / m). The lines 1014a and 1016a therefore require a pulse transit time of (120 ■ 5.33 nsec / m) = 640 nsec. The desired dead distance between consecutive Data words is 7 ″ of the word length, e.g. B. 250 nsec. Thus, the delay line becomes 1029 (Fig. 18) is set for a delay time given to

D = L + S- T

where L is the length of the phase-coded data word, 5 is the desired word separation and T is the sum of the transit times of a pulse through lines 1014a and 1016a. In a numerical example, the artificial delay is D

D - (1000 + 250 - 640) = 610 nsec.

The operation of interrogating each transceiver unit 111 through the interrogation link 1016 is used in conjunction with FIGS. 43 to 48 are described in more detail below.

A data word consists of 20 bits, of which bits 1 to 3 are the preamble, bit 4 the parity bit, bits 5 to 8 represent the exponents, bit 9 the sign bit and BiU 10 to 20 represent the Matisse. The analog-to-digital converter 126 converts the data into binary Variable character code (NRZ code) format-controlled This code is shown in FIG. 22 represented by diagram 6a. A bit interval is 50 nsec. Since there are 20 bits, the word length is 1000 nsec. By doing In the illustrated example, bit 9 is assumed to be a one bit, while the remainder are zero bits.

In the code converter 128, the data is format-controlled in the phase-encoded NRZ pulse code, as in Diagram 66 of Fig. 22 is shown. For a zero bit is a logic level over- ■> at every bit interval limit gear available. For a one bit (e.g. bit 9) there is a logic level transition in the middle of the interval. at Lack of data, e.g. B. between data words, the signal level remains zero. The leading edge of a first bit of a data word must always have a positive going

ίο be impulse.

Phase-encoded NRZ data (diagram 6c according to FIG. 22) are converted into a phase-encoded RZ (return-to-NuII) pulse code by the transmitter 1066 Transmission in constant current operation in the data ver binding 1014 converted. "No data" is through represented a logic zero level. The logic level is noticeable 50 nsec before the start of a data word -5 V for a bit interval, which ensures a positive leading edge for the first data bit is steady. There must be a polarity transition from - V to + V (or from + V to - V) with every bit interval limitation for a zero bit. In addition, a one bit requires a polarity change in the middle of the interval (/. B. bit 9). Falls at the end of a data word the logic level is - V for 75 nsec and then goes to zero.

From the diagrams 66 and 6c of FIG. 22 shows that at least one positive going pulse must be present within two bit intervals. For a full description of various pulse codes is found in The Interface Handbook by Kenneth M. True pointed out.

It is desirable to use a self-clocking pulse code, z. B. to use the above, because the Clock 1108 in each transceiver unit (Fig. 19) are asynchronous to each other, although they operate at identical frequencies. In the absence of one self-clocking pulse codes would have to be assigned separate timing pulses to the data word, where- would be complicated by the system.

Data that arrive at a transceiver unit 111b (FIG. 17) from a transceiver unit llle below the connection are transmitted by the data receiver 1068 (FIG. 18) in the repeater network 114 added. The regenerator 1060 either takes a local data word from the storage register and the transcoder 128 or a data word below the link from the receiver 1068. The regenerated word is shown on line 1063 in

so abandoned the data transmitter 1066 for transmission via a data connection 1014 to the next transmitter-receiver unit 11 1a above the connection.

In Fig. 19, one of the repeater circuits 114 is im shown individually The receiver 1068 is a line ar amplifier 1100 with positive feedback to the Er targeting controllable delay effects (hysteresis). The amplifier 1100 amplifies incoming phase encoded RZ data transmitted over the data link 1014, and due to the hysteresis se he converts them into corresponding phase-coded NRZ logic level around. The regenerator 1060 has a OR gate 1102, which is on line 1103 either data from the receiver 1068 or local data from the line 1057, which is connected to the output of the

Memory register 128 (Fig. 18) is connected

A data detector circuit 1104 indicates a zero crossing, particularly the transition from negative to positive at the first bit interval boundaries, whereby

a data synchronizer 1106 becomes effective. The data detector 1104 also shows the lack of data, for example the gap between data words if there are no polar transitions at the output of the OR gate 1102 occur within a certain time interval. Thus, line 1101 only takes Data words from sensor groups downstream of the connection in question, while line 1103 either local or such data words receives the sensor groups supplied below the connection come.

Each transceiver unit 111 has a crystal oscillator or clock with exactly 80 MHz. The clocks in the corresponding transceiver units are freely oscillating clock generators and are therefore asynchronous to one another. Because of the effects of the throbbing signal and the radio frequency interference from communications link 1014 are phase encoded Data word distorted. Furthermore, the signal levels are weakened due to the line losses. It is therefore advisable to amplify and regenerate the data pulses at each transmitter / receiver unit, to regenerate the data pulses at each transmitter-receiver unit, the data pulses must but must first be re-synchronized with the local clock.

The local clock 1108 (FIG. 19) synchronizes phase encoded NRZ data words in the data synchronizer 1 lot. Line 1107 receives newly synchronized data going to transmitter 1066 Control of a control pulse from line 1112, which is connected to the data detector 1104 is sent will. Line 1113 from data detector 1104 also sends control pulses to the data synchronizer 1106.

The regenerator and synchronization network 1060 comprises flip-flops 1070, 1071, a counter 1072, a crystal oscillator which is the clock 1108, and a block 1074 which divides by "2". First the flip-flop 1071 is reset, whereby its ζί-output is set to ZERO and the (^ -output of the fip-flop 1070 is reset to ZERO. The divider 1074 is reset so that no clock pulses over the line 1109 to be counted 1072. When the first bit of a data word is received via line 1103, the first data pulse on line 1103 is also a positive-going pulse, which results in a change from ZERO to ONE. This positive-going pulse clocks the Q- The output of the flip-flop 1071 goes to a ONE, which enables the flip-flop 1070 and the divider 1074 via the line 1113. The divider 1074 transmits a 40 MHz clock pulse over the line 1109 Phase is with the positive going data pulse on the line 1103, the flip-flop 1070 triggers so that the logic ONE at the D input is transferred to the (^ output as a regenerated, newly synchronized data pulse.

The data detector 1104 has the counter 1072 to detect the presence of a data word on the line 1103 to capture. The first positive going pulse of a data word on line 1103 sets the Counter 1072 back. The clock line 1109 sends one Gable 40 MHz clock pulse to counter 1072. The counter counts three clock pulses. Since the impulses all 25 nsec occur, the three counting steps determine a time interval of 75 nsec, i.e. 25 nsec more than one bit interval amounts to. If the counter 1072 does not respond to a positive data pulse within the interval is reset by 75 nsec, it delivers a carry pulse to line 1114 after three pulses to reset flip-flop 1071 and cause ZERO level to appear on line 1113, whereby the flip-flop 1070 and the divider 1074 are reset and the transmitter 1066 via the line 1112 ineffective will.

Fig. 20 shows a set of timing diagrams, which explain how the regenerator 1060 works. The first diagram 1200 shows binary data that is used as a phase-coded N RZ data word are format-controlled. The bit interval is 50 nsec. For a NULL bit there is no polarity reversal between the bit interval boundaries, while for a ONE bit the polarity changes in the middle of the interval. A polarity reversal must occur at each bit interval boundary. the Bit interval limits are indicated by arrows above the diagram. The bit values are between the Parts inscribed. A complete data bit consists of 20 bit intervals and is therefore 1000 nsec long. the end the diagram shows that at least one positive going pulse is within two bit intervals must be present. The operation of the data detector 1104 (FIG. 19) is based on this feature.

The second diagram 1202 of FIG Sequence of 80-M Hz clock pulses 1224. Diagram 1204 shows the waveform of an incoming Data word that is converted by the receiver 1068 from the phase-encoded RZ pulse code to the phase-encoded NRZ pulse code has been implemented conditionally the original pulses, which are shown in diagram 1200, are worsened by noise and interference been. The pulses picked up are out of phase and unbalanced.

According to the F i g. 19 and 20, the first positive transition 1220 of the data word clocks the Q output of flip-flop 1071 to a ONE (see diagram 1204). The logical ONE on line 1113 generates a control signal 1222 to divider 1074 and flip-flop 1070 (see timing diagram 1206). The next The 80M Hz clock pulse 1224 that is closest in phase to the rising bit edge 1220 becomes the first 40 MHz clock pulse 1226 (see timing diagram 1208).

The clock pulse 1226 clocks the logic ONE at the D input of the flip-flop 1070 into the (^ output via line 1107 as the leading edge 1228 of the first newly synchronized, regenerated data bit. As long as a logic EI NS is present on lines 1112 and 1113 a transmission control signal 1230 activates the output transmitter 1066 (timing diagram 1212). The data bits on line 1107 can then be converted from phase-coded NRZ data into phase-coded RZ data for transmission to the next transmitter-receiver unit above the connection currently under consideration When the first rising bit edge has been re-synchronized, the 40 MHz clock pulses are re-synchronized and regenerate the remaining data bits. Timing diagram 1214 shows the output of counter 1072 on line 1114. If a data word exceeds three 40 MHz clock pulses remains at ZERO, the counter 1072 outputs a carry pulse 1232 to the flip-flop 1071 and the counter 1074 and switch the transmitter 1066 'ineffective.

The transmitter 1066 (Fig. 19) has a voltage to current converter 1076 and an NRZ to RZ converter 1077. In order to reliably transmit data via a

connection, ζ. B. transmit a coaxial cable / u, the signals must be AC signals without a low frequency component. A transmission in constant current mode can be used here avoid the need to use broadband dynamic 1068 receivers. Loss of voltage on the data connection 1014 results in a considerable weakening of the signal. A transmission in constant current operation results in essentially constant Voltage level at the terminating resistor 1150 at the input of the receiver 1068, regardless of losses in the data connection 1014 between neighboring transmitter / receiver units 111.

In order to achieve a transmission in constant current mode, the phase-coded data words are converted from a voltage into a constant current by the current converter 1076. The voltage controllable logic gate 1075 has both inverting and non-inverting outputs 1075J and 10756. Resistors 1073a, 10736 (which have the same value R ) and transistors 1078a, 10786 convert the voltage levels at the output of gate 1075 into constant currents.

The bases of the transistors 1078a and 10786 are set at a voltage Vi, where V, is equal to the ZERO state of the outputs 1075a and 10756 of the logic gate. The exact voltage of the ZERO state depends on the type of logic selected. The voltages Vr appearing across resistors 1073a and 10736 are output voltage states (V, - Vi) and (V _b - V _x ). That is why the current is through the two resistors

high - (V _R , ONE state - V _x ) IR

= C ^ ä. ZERO state - V _x ) ZR = 0.

The output stream on data link 1014 is therefore

that is in

- Ibhoch +

changes for a polarity change within a bit interval (Fig. 22). Since la _niaJ rig and Ib " _in i _ri f = zero, the current in the data transmission connection 1014 becomes (lah high - Ib high) with a bit polarity change. This applies to data in the bipolar NRZ code. At the end of a data word there is a low-frequency component due to the time constants of the transformer 1079 and the coaxial data connection 1014. To suppress the low-frequency component, the NRZ signal is converted into RZ format by the circuit 1077 the line 1112 becomes ineffective, the switch 1077a is applied to the voltage V ₁ . For simplicity, switch 1077a is shown as a mechanical switch; in practice, however, it is a semiconductor switch, e.g. B. a transistor (field effect transistor). When the end of a data word has been detected by data detector 1104 (FIG. 19), a pulse on control line 1112, which is connected to data detector 1104, causes switch 1077a ü switches to V ₂ . V ₂ is equal to the ONE state of outputs 1075a and 10756, so that transistors 1078a and 10786 are turned off. The current in transmission link 1014 goes to zero so that the bipolar re N RZ output of transformer 1079 converted into the bipolar, phase encoded RZ pulse code will. The windings 1079a, 10796, 1079c of the transformer 1069 have a turns ratio of 1: 1: 1. According to FIGS. 17 and 21, the central station 2

ίο a Dalen receiver 1028, which receives the phase-coded RZ data words, which are transmitted by the transmitter-receiver units 111 via the data transmission link 1014, d. H. over the triple redundant Coaxial connection Dl, D2, D 3 in Figure 5, transmitted

i ^r ; will. The data receiver 102S translates the phase-coded RZ data words into a binary NRZ pulse codc first as floating point numbers and then converts them into the data words with fixed point numbers. The data words with a fixed comma are stored in a Channel sequence matrix is stored in an allocation memory of group form facility 1030, as will be explained below. Each elementary seismic sensor unit is a subset because, in the case of the described embodiment three individual Dc having tektorcn. The output signals from an An number of such subgroups are combined in the group forming device 1030 so that one for a much larger one, d. H. elongated group gives characteristic composite signal. That formed The composite signal is transmitted to a format control device 1032 and from there to a magnetic tape recorder 1034, in which the signals are recorded so that they are later available for evaluating a seismic cross-section of the earth's strata stand.

At the beginning of a seismic measuring process, a calibration address operation is initiated at the central station 2. An interrogation pulse is sent by the main control 1019 via the interrogation connection 1016 to the corre Chcenden transmitter-receiver units 111 sent. There Each transceiver unit indicates the interrogation pulse, a data word is in the data receiver 1028 sent back over a data link 1014. A time converter 1015 must measure the length of time between the Transmission of the calibration interrogation pulse and the arrival of the resulting data words from the transmitter / receiver units 111. Each of the data words from a line delay is of course assigned to each transceiver unit. The time delays are den encoded as binary numbers to form an address code and are iin Address memory 1017 stored. During normal operation, time converter 1015 measures the interval between the corresponding interrogation pulse sen and the returning phase encoded data words. The time intervals are compared with the stored address codes. The address store 1017 then identifies each recorded data word with respect to the originating transceiver unit and causes the group shaper 1030 to put the recorded data word in the correct place in the Matrix of a core memory uses.

Fig.21 shows a schematic representation of the Group form device 1030. This group form a direction 1030, a control unit 1081 has an assignment input memory 1083a, 10836, a memory write controller 1037, a data channel scan memory 1047, a Read controller 1049, a multiplier circuit 1053

and 10536, coefficient read-only memory (ROM) 1055, adder 1064a and 10646, accumulator registers 1065a and 10656, an output memory 1080 and the microprogram memory (ROM) 1067 which is read-only memory.

The receiver 1028, as previously described, takes the phase encoded data words from the transceivers purple to Hin below the connection and converts the phase-coded data center data keeper into NRZ binary numbers with floating point, which are then reformatted into fixed point numbers. Simultaneously, the time counter or converter identifies 1015 and address memory 1017 upon reception of the data words each number in relation to its origin in the form of the transmitter-receiver unit number and the data channel number. The fixed point numbers from the receiver 1028 are written to the group form facility 1030 and stored in the allocation memory 1083, where they are transferred to the data channel sequence under control of the control device 1081 and the writing control 1037 after a data channel identification has taken place via the address memory 1017.

The data channels are numbered from 1 to 500, with the first elementary seismic sensor unit is started, that of the next transmitter-receiver unit arranged below the connection purple is assigned, and which end with the last seismic sensor unit, that of the furthest, below correspond to the connection arranged transmitter-receiver unit Hin. The phase encoded data words however, the number sequence of the sensor group from the communication link is not used 1014, they come, as explained above, for example via the transmitter-receiver channel 1 from all transmitter-receiver units purple. There, then as a transmitter-receiver channel 2 from all transmitter-receiver units HIa to Hin, etc. In the data channel numbering is equivalent to

- Channel 1 of the sender / receiver IHa channel in the Allocation memory matrix 1083a,

- Transmitter / receiver 1116 channel 1, corresponds to the Data channel 11,

- Transmitter / receiver unit HIc, channel 1, corresponds the data channel 21 and

- Transmitter / receiver unit Hin channel 1, corresponds to the data channel 1 + 1On.

The transmitter / receiver channels 0, 11, 12 and 13 are in the above-described embodiment auxiliary channels. It is the function of the allocation memory 1083a (Fig. 21), the data with a fixed comma arriving from the receiver 1028 in the correct data channel sequence put together in a memory matrix and the auxiliary channels in their correct sequence in an auxiliary channel memory location 10936 to separate. When a scan of the seismic data and the data in the auxiliary channel have been written into the allocation memory 1083a, 10836, the data channel signals from the allocation memory 1082a into the data channel scan memory 1047 and the auxiliary channel data 10836 in transfer the output memory 1080.

The digital numbers stored in mapping memory 1083 represent the signals from the 500 elementary ones seismic sensor units, each of which forms a short subgroup. The control store 1067 and coefficient memory 1055 are preprogrammed to select the digital signals from Combine subsets to form a composite digital signal that is characteristic for a much larger desired group. The ■ 5 evaluation or the weight that the digital signal of a individual subgroup contributes to the total composite digital signal is made by the coefficient memory 1055 controlled. The procedures and techniques for applying weighting coefficients are explained below.

The seismic data channel signal in the scan data channel memory 1047 is read out in the data channel sequence, where data channel 1 is the first and data channel 1On is the last. The data channel signals are transmitted to multipliers 1053.7 and 10536 via data trunk line 1082. Under control of the control unit 1080 and the programmed group pattern stored in control memory 1067 each data channel signal is multiplied by the corresponding weighting coefficient stored in the coefficient memory 1055 is stored. When the signal from a data channel is not used in a group should be, its coefficient will be zero and thus the result of the multiplication is zero. The rated Data channel signals are then applied in adders 1064a and 10646 to the outputs of registers 1065a and 10656 added. The accumulated results in registers 1065a and 10656 correspond to the sum of those evaluated Data channel signals. The control unit 1081 transmits depending on the memory 1067 the Contents of registers 1065a and 10656 in an output register 1080 as a data sample for each composite Group, if the previously programmed number of individual data channel signals that each combine

J5 set group has been totaled. The process continues until all of the data channels are in the scan data channel memory 1047 processed into composite group signal samples and transferred to the output memory 1080 have been transmitted. The contents of the output memory 1080 then contain a composite sample Signal samples for the composite groups. Auxiliary channel data is similar in Way under the control of the control unit 1081 format-controlled.

For example, assume that a seismic cable assembly 500 has individual short subsets own. The output signals from successive sets of 20 subgroups can be combined in this way will be that composite signals are generated that represent 25 much longer groups. By using dual multipliers 1053s, 10536, dual adders 1064a, 10646 and dual registers 1065a, 10656 can take some of the signals from some of the 20 subgroups, which each form one of the successive groupings, with neighboring ones Groupings, d. H. Sentences to generate composite signals, the 50 overlapping, longer ones Represent groups, be connected.

The content of the output memory 1080 is sequenced

ω tiell on the format controller 1032 and then on the recorder 1034 can be transferred. When this processing cycle is completed for the first scan is, the new data obtained in the next scan is stored in memory 1083a and

10836 rearranged. After the processing of the result of the first scan, as determined by the control unit 1081, has been completed, the new data are used for the scan data "n-StiM" i-mwM * i "" r

61 62

transferred and the processing days for the formation of Si the other 49 transmitter-receiver units (if

Signal patterns of a second scan are available for the next 50 transmitter-receiver units in total

compound Gi ippe begins. are) on. regenerates and transmits them. The last one, the 50.

The process explained above is under control-transmitter-receiver unit, is of course only its own

tion of the main control unit 1019 continued until the s local data word.

Recording and processing cycle completed- To all channels in all, transmitter-receiver units

sen is to be queried, so an S ! -pulse and 13 52-Im-

The system described so far works as follows: transmit pulses during a scan cycle. Thus i A number of transceiver units 111 are in FIG. 1, data words in the data receiver 1028 in FIG

regular intervals away with respect to the zen io one time series / channel series two-stage multiplex cycle ip

central station 2 arranged each transmitter-receiver transmitted. This means that data words from the §

unit has fourteen input channels with which seismic-speaking transmitter-receiver units UIa to 1 In |

see sensor subgroups, as well as a channel selection depending on the query pulse transit time between Sf

device, namely the multiplexer 122, and one seen successive transmitters / receivers ge f

common signal conditioning electronics of the transmitter are separated. An additional delay in every _f-f

Receiver unit are connected.

are ten data channels. The rest are test and auxiliary know-how of the individual query / response pulse groups. %

nalls. The output of the common signal condition data words from the corresponding channels within ψ

nierelektronik is half the WiederhoJernetzwerk 114 of each transceiver unit thus be of- f

tied together. Within each of the transceivers 20 depending on the channel selection sequence;

Interrogation network 116 is arranged in units. separated.

The repeater networks 114 of the transceiver If the data words at the data receiver 1028 to \ , ;; units are all connected in series and come with that. they be- t data receiver 1028 in the central station via the orderly ΐ and temporarily stored in a channel sequence matrix broadband communication link 1014 connected in the allocation memory 1083a. 25 net The first data channel of the first transmitter-receiver The query networks 116 are all connected in series 'tion 2 via the interrogation connection 1016, which is assigned three times. Thus, depending on the first redundant line / PI, IPZ IP3 of FIG. 30 11, 21, etc. added. Depending on the periodic at the beginning of each sampling interval, the second interrogation pulse are data words from the z. B. at the beginning of every millisecond, sends the main data channels 2,12,22, etc. added, and so on control unit 1019 a broad S1 query pulse via. Since the interrogation network preprogrammed that it interrogates signal samples which are identified by factory 116 in each transmitter-receiver unit U1 of the 35 selected sets of seismic subgroups 51-impulses, the channel selection device comes from the allocation memory 1083a. The service on channel no. 0 is reset. The digital data selected signal samples are transferred to the data channel response from the last channel of the preceding sampling memory 1047, from there to the multipliers 1053a, output is transferred to a self-clocking, phase-coded RZ-10536 and converted with selected evaluation code data word and via the transmitter 1066 of the 40 efficient repeater network 114 of the transmission connection, controlled by the coefficient memory, 1055 multiplied. A narrower, a single, composite signal sample, the 52-pulse, is then transmitted from the main control unit 1019 to a significantly larger group with preselected own, precisely 71.4 μβεϋ later. When each one represents stocks. The composite data who-sender-receiver unit receives the 52-pulse and identifies it in the output memory 1080 for the subsequent one, the multiplexer 122 is switched to the format control device 1032 and to channel no. 1 as a channel selector transmission. The seismic signal, subsequent recording in the recording device, which is present in channel no. B. on a magnetic tape, stored, raised to a certain level and as phasenco- 50 It follows that the previously described seismidized NRZ digital word ie as a local data word this data processing system represents a single seismigital. The local data word is provided in a phased cable, which converts the formation of a sent-coded RZ data word and is switched to the desired seismic sensor group configuration data transmission connection 1014. from a variety of subgroups. It is not necessary that each transceiver unit transmits a 55 first, physically the seismic cable or local sensed data word. Then it expects the other components of the data processing system at the arrival of a remote data word from the next to change place of use in order to receive different groups arranged downwards with respect to the connection, the changing geological conditions transmitter-receiver unit and subsequently the grown are.

Arrival of a data word out of the downward direction with reference to Fig. 60 An explanation will be given of FIG. 23

the connection arranged transceiver input to 35.

that is adjacent to the next, etc. Each remote Fig. 23 shows, similar to Fig. 1, a schematic

te data word recorded in this way is re-representation of seismic exploration arrangements that and show upwardly in relation to the link one embodiment of a seismic survey to the data receiver 1028 to the central station 265 or exploration system. A ship 10 with a

transfer. Thus, the transmitter-receiver transmits a large cable reel 2054, which is attached to the stern, HIa is initially called its own local data word and drags a long sea-scismic cable 2056, the then removes removed data words sequentially from scrolls 2054. The sea floor is through

the horizontal line 2058 is indicated, and various geological stratum interfaces are indicated by horizontal lines 2060, 2062 and 2064

The cable 2056 has a first section 1056 ' closer to the ship 10 and a remote section 2056 "that is further away from the ship e.g. B. 1.875 m apart and each elementary sensor unit which consists of three sensors has a length of about 3.75 m, the center-to-center distance for adjacent sensor units being 5.625 m.

First, the arranged at the position 2066 elementary sensor unit explained in the sensor unit at the location 2066 receives reflections occurring in succession after an explosive charge used at the point 2068 near the stern of the vessel and in the vicinity of the adjacent end of the cable 2056 to detonate became. Following the initial pulse, known as the first deployment, which usually travels directly through the top layer of water to the sensor unit 1066 , the first reflected seismic wave from the sea floor 2058 comes back. This first reflected signal, which is picked up at the sensor unit 2066 , travels along the relatively short path 2070. When it hits the sensor unit at the point 2066 , the beam or path 2070 forms a relatively flat angle θ \ with the horizontal. Subsequent reflections at geological interfaces 2060 and 2062 follow paths that embody lines 2072 and 2074. These rays successively form larger angles θ ₂ and θι with the horizontal. Thus, the direction of the signals which are incident on the sensor unit 2066 changes during the recording of the seismic reflections and, in particular, the angle of the recorded signals relative to the horizontal increases with increasing time. Further, the signals reflected along beams 2070, 2072 and 2074 and successively picked up at sensor units 2066 can be simplified as a representation of a trace of reflected signals from points along vertical line 2075 (including points 2070 ', 2072' and 2074 ').

In Fig. 23, an additional sensor unit 2076 is shown at the far end of the seismic cable. the end For convenience, the inner half of the sea seismic cable is numbered 2056 'and the outer half is labeled 2056 ″, with the sensor unit 2076 at the outer end of the distant outer half Half of the cable 2056 ″ is arranged. At a later point in time, the sensor unit 2076 takes signals reflected from geological interface 2062 along path 2078. To an even later one In time, the sensor unit 2076 takes reflections along the path 2080 from the current geological Interface 2064. In particular, it should be noted that the sensor units 2066 and 2076 signals from a record a certain slice at different angles and at different times.

As with other types of wave propagation analysis, the waves can be represented by wandering spherical wavefronts or rays. Furthermore, the waves according to rays 2072 and 2074 are refracted at the interfaces 2058 and 2060 at angles which depend on the physical properties of the layer.

Of course, geological interfaces such as those in FIG. 23 shown horizontal interfaces 2058, 2060, 2062 and 2064, unusual and not of particular interest to the geologist. Of greater interest are geological anomalies, such as e.g. B. faults, clumps or collapsing interfaces. In Figure 23 the inclined plane is shown in 2082, which gives a positive angle of incidence relative to the horizontal plane 2064 The broken line showing an incidence plane 2082 represents the subject matter which is in connection with the Figure 24 and 25 discussed below .

The seismic path 2083 (FIG. 23), which is shown in dashed lines, meets the plane of incidence 2082 at the point 2083 '. in the case of a plane that slopes downward away from the direction of movement of the ship, using the geometry according to FIG. 2 shows the resulting seismic signal displayed on the sensor unit 2076 in intensity compared to the signal which is reduced or incident by reflection from a plane which is inclined in the opposite direction.

This is explained in detail in connection with FIGS. 24, 25 and 30 explained. On a qualitative basis, however, it can be stated that conventional seismic groupings are more sensitive to signals arriving vertically at the grouping and are less sensitive to waves arriving at relatively small angles of incidence. Furthermore, this increased sensitivity is more pronounced for conventional seismic groupings at higher acoustic signal frequencies. As shown in Fig. 23, the seismic path 2083 against the sensor unit 2076 is at a smaller angle of incidence to the horizontal than the path 2080. If the plane 2082 is inclined in the opposite direction. If the angle of incidence at the sensor unit 2076 is even closer to the vertical and the response intensity would be increased accordingly. This phenomenon is discussed on a quantitative basis below in connection with the description of FIG. 24,25 and 30 considered.

In the present case, the difference is in seismic Monitoring results obtained in a moving direction in comparison with the so the opposite direction of movement is referred to when carrying out a marine exploration. As stated above, this difference is due to the difference in the direction of transmission of the seismic The energy required for exploring the sea with a seismic impulse from the ship. at Systematic land explorations can of course initiate the seismic impulse from various locations length, including locations at the rear or front of a linear array of cables to the traverse. Applying the present analysis to land surveys, the situation is seismic Pulse source relative to the seismic cable is a determining factor.

Fig. 24 shows a graphic representation of the relati-M ven responses to reflected signals of an unguided Sensor group with the known configuration shown in FIG. 26, which are located at a distance of 300 m from the launch site along cable 2056 in Fig. e. 3

is located at various indicated frequencies and following a one second time interval from launch along the reflection path to the sensor array. The response at 200 Hz is identified by a consecutive x, at 100 Hz by a consecutive +, at 50 Hz by small triangles and at 20 Hz by small circles. The one-second line interval, together with the speed, determines the depth of penetration of the reflected signals. The speed according to FIG. 28 amounts to 1800 m / sec for a reflection time of 1 second; the penetration depth is therefore about 900 m. 24, the angle of inclination corresponding to the angle between the dashed line 2082 and the horizontal line 2084 in FIG. 23 is plotted on the horizontal axis. At a displacement of about 300 m from the launch site, the maximum response occurs at all frequencies at an angle of about -10 °, which corresponds to seismic waves that fall approximately vertically on the sensor group. This maximum response condition is indicated by vertical line 2084 in FIG. 24 shown.

Most of the seismic energy is so far at relatively low frequencies from the F i g. 24 obvious reasons. Note that on the second vertical line 2086 in FIG. 24 that corresponds to a positive tilt angle of 10 °, practically no energy at 200 Hz from the sensor group is recorded.

It should also be noted that along vertical line 2086 the energy absorbed at 100 Hz has a level of approximately -18 db. F i g. 25 represents a more extreme condition than that in FIG. 24 represents an unguided arrangement. It applies to a distance of about 1200 m from the launch point to the sensor receiving point, a relatively low speed of about 1500 m / scc, a characteristic of water or near-surface materials, as given in some places, and a period of only 1 see corresponding to reflections from a relatively shallow geological layer. As can be seen by referring to vertical line 2088 in FIG. 25, at an angle of + 10 ° even the 50 Hz seismic signals are clipped and only the very low frequencies, e.g. B. the frequencies of 20 Hz shown by plot 2090 are indicated by the sensors. Certain legs for 200 Hz are shown at 2092, 2094 and 2096. However, these do not provide any important information because they are incorrect, out of phase or have other anomalies.

The diagrams according to FIG. 24 and 25 show in detail the problems with fixed, unsuccessful groupings occur of the kind discussed in some of the publications mentioned above.

In particular, FIG. 26 shows a group of 26 elements which provide a uniform evaluation of the Use sensor inputs and a variable distance. The total length of the group is 63 m, and the The distance is given by the following numerical values: ± 3 ', ± 8', ± 14 ', ± 19', ± 25 ', ± 30', ± 38 ', ± 44', ± 52 ', ± 61 ', ± 71', ± 80 ', ± 105', where the 26 elements from the center of the group by the specified number of Meters are staggered.

In Fig. 26, the uniform height of the lines 2028 indicates the uniform rating of the sensors, the horizontal positions indicate the relative distance of the sensors along the seismic cable. The resulting sensitivity is symmetrical about the vertical center line, is relatively wide and only differs from waves running horizontally. The sensor group of FIG. 26 was used when creating the diagrams according to FIGS. 24 and 25 used
The group of FIG. 27 consists of ten elementary sensor units, each of which contains three detectors. In the sloping group of FIG. 27, the sensor units 2102 and 2104 at each end have a rating of "1" compared with an increasing rating of 2, 3, 4, 5 for the sensor units towards the middle of the group, with the two sensor units 2106 and 2108 in the middle Have ratings of "5". The elements of the group are arranged at a uniform distance from one another and extend over a total distance of 69 m from the first sensor to the last sensor.

This inclined group of FIG. 27 has a response characteristic that is fairly sharply defined Main lobe. As will be explained below, the tapered configuration of FIG. 27 may be used in connection with the point discussed herein.

28 shows a diagram in which the speed in meters per second is plotted against the reflection time in seconds. In Fig. 28, the low speed line 2110 appears, beginning with V /. as a horizontal line indicating a constant speed of 1500m / sec. This is the speed of seismic waves in water or near the surface of the earth; it is especially important for a wave that is nearly horizontal in water. However, the high speed line 2112, labeled Vn , increases in speed with increasing depth through the earth (as opposed to J5 for water conditions). In the case of longer reflection times, the root mean square value of the speed in meters per second increases sharply up to a maximum value for a reflection tone duration of 4 seconds of 3300 m / sec. The high speed line represents the actual speed conditions in many areas of the world. The analysis of FIG. 24 is based on the high speed Vn characteristic of FIG. 28, while FIG. 25 and 30, which represent more extreme conditions, on the characteristic V /. the F i g. 28 are based.

A large number of groups are longitudinal of a seismic cable, and each of these groups can be individually directed so that they is sensitive to seismic reflections resulting from unspeakable, predetermined depths of a geophysical terrain under investigation. This can be achieved by initially generating a large number of seismic signals from elementary seismic sensor units, which are arranged offset along the cable, are transmitted. Then a large number, maybe 30, 50 or more groups, spaced at 30.50 or more Set along the cable from the signals picked up by the elementary sensor units will. These groups, which are staggered along the cable, are directed to be seismic Signals from selected depths along adjacent vertical lines of the geophysical under investigation Capture area. This direction-sensitive M wedge can be achieved by appropriate delay signals originating from neighboring elementary sensor units. This is followed by the seismic Signals from neighboring vertical lines

combined so that they have a cross-section or a compound geophysical measurement of the terrain to be investigated.

In order to achieve the correct delay value between signals from neighboring elementary sensor units which form a group, it is important to determine the differences in the arrival times of seismic signals at the neighboring elementary sensor units. Fig. 29 and the mathematical investigation below show how this delay can be calculated. In Fig. 29, a seismic pulse from the launch site 2116 is reflected by the geological boundary layer 2118 into the sensor group 2120 , the seismic signals traveling along the beam paths 2122 and 2124 .

In the following mathematical analysis, the letters "s", "x" and "d" refer to the distances and points shown in FIG. For convenience, point 2116 is reflected in point 2126 , which is the virtual image of point 2116 relative to plane 2118 .

The following definitions apply to the mathematical investigation:

χ - distance of the sensor group from the point of launch

ν - traveling speed of the seismic wave d - depth of the reflective boundary layer
s - path length of the reflecting signal
f - duration of transmission of the reflected seismic wave along the path

ίο - transmission duration of the reflected seismic wave over the distance 2d.

It applies

In the geometric illustration according to FIG. 29, the following applies

s = ] / x ² + 4d ² (H)

S = W = | / * ² + V ² f _O ^z (I)

Squaring this equation shows that ί and ίο are given by the following expression:

v ² t ²

v ² to ²

v ² tn ² - ν ² 1 ² - χ ²
From equation (I) it follows

and the derivative

df _

dv

ν Vx ¹

(K)

(L)

If one puts equation (K) into equation (M), one obtains

d /
dx

ν V _x ² + ν *, ² -χ ²

(N) Assuming the following values:

χ = 1800 m
ν = 21C0m / sec
/ = 1.0 see

and a distance between the elementary sensor units dx = b ni can be resolved for d / as follows:

1800

^d ^ ^d- w- ⁶ ' ² ' ^45ffi5ec

This represents the desired delay between elementary sensor units which are offset 6 m from one another, which is necessary so that the seismic signals arrive at the same time at the time t at neighboring units in a group.

The angle θ in Fig. 23 at the point in time f = 1.0see

θ - cos " ¹ - - cos" ¹ - - cos " ¹ 6/7 - 31 ° J vf

If the time duration / increases, reflections arrive from deeper layers, θ increases and the required delay between the elements of the group, which are arranged on the Sielle 2120 (Fig. 29),

jo takes for the maximum response and the maximum Signal-to-noise ratio.

F i g. 30 shows a diagram for comparison with FIGS. 24 and 25, where the response is above the Layer inclination angle is applied. In Fig. 30 are

j5 the individual groups, having a strong directional configuration of the type shown in Fig. 27, arranged along the length of the seismic cable and directed to receive energy reflected from a horizontal plane at the depth equal to the elapsed time from the point of time of the launch up to the point in time when seismic reflections were recorded. This corresponds, for example, in connection with FIG. 23 directing the group located at location 2066 such that maximum energy is drawn from the ocean floor 2058 along path 2070 . At a slightly later point in time, the group 2066 is directed further downward so that it absorbs energy from the interface 2060 along the path 2072. This change in direction can be achieved, for example, by changing the delay between the various elementary seismic sensor units which form the group at point 2066 along the cable. F i g. 30 represents the addressing of a steerable group

«Pe which is centered at a location 2400 m from the launch site and which" looks "in a direction corresponding to an elapsed time for the arrival of reflected seismic signals equal to 1000 seconds. It is based on the Fig. 2110 (Vi) low speed line. 28, and is thus full of F i g. 25 comparable. In Fig. 30 is similar to FIG. 24 and 25 the response at 200 Hz by successive χ, at 100 Hz by successive +, at 50 Hz by successive small

b ¹ ) Triangles and indicated by successive small circles at 20 Hz. At every instant in time, the group is directed to absorb energy from a horizontal geological boundary layer, which in

is arranged at the correct depth so that reflected signals arise on the sensor units. In contrast to the arrangements according to the F i g. 24 and 25 shows the diagram according to FIG. 30 a maximum response all frequencies at a layer inclination angle of 0 ° corresponding to the center line 2128 in Fig. 30. That Response at any frequency including curve 2130 of the highest frequency 200 Hz is substantial symmetrical to line 2128. For negative .slayer inclination angles the 200 Hz claim curve hits the value of -40 db at about 22 °, as through the point 2132 is shown, and for positive stratification angles! the intersection is at 28 ", as indicated by location 2134 shown. The loss of 100 Hz signals at the slope angles of ± 15 ° is less than 3 db, and "the loss of the 50 Hz signals is of the order of magnitude from 1 to 2 db. This is fundamentally in contrast to the diagrams according to FIG. 25, where none useful information at the 50 Hz, 100 Hz or 200 Hz frequency levels at the angle of inclination of + 15 ° can be obtained.

Arrangements, the individually and continuously changeable, directed groups in the longitudinal direction of the Using seismic cables have the additional advantage that they are largely insensitive to the Direction of the profile are. In particular, if a seismic profile runs from east to west, for example, in which a system with the response according to FIGS. 24 or 25 would be an essential different results can be achieved than with the same system with a profile from west to east. Used If, on the other hand, an arrangement with the response properties according to FIG. 30 is used, no essential Determine the deviation between the seismic profiles in both opposite directions.

In FIG. 31, the cable 2152 which is connected to the cable 12 according to FIG. 1 and the cable 2056 according to FIG. 23 can correspond to a large number of cable sections 2156a, 21560,2156c, ... 2156 /? on. These cable sections are connected to one another by electronic connector modules 2164a, 21646, 2164c, ... 2164n, which the Connector modules 13 correspond to FIG. 1 and thus contain the transmitter / receiver.

The cable assembly 2152 can be placed in water in the course of a sea seismic exploration, as shown in Fig.23, or in the case of a Land cables spread over the terrain to be explored, using the seismic sensors, which are then geophones are resting on the surface of the earth.

The rest of the Tci! the arrangement according to Fig. 3! irn The block diagram is arranged at the central station 2 in the ship 10 or a towing vehicle or the like; In certain cases of application, certain processes described in FIG. 31 are shown at a central Processing site can be carried out remotely from the seismic survey. As in Fig. 31 shown, is the data word output from the cable into the data receiver and system control unit 2172, for example into the data receiver 1028 of FIG. 17, and the seismic data received from the cable on unit 2172 can be processed to include a) a seismic monitor section 2174 for review by the scout team and b) a final cross section 2176 high resolution for geologists. Seismic data from the control unit 2172 are sent to a first Group form device 2178 transferred to the 17 corresponds to group form device 2130, and also to a conventional monitor writer Transmitted 2180 for the seismic intercepts. The output from the group form device 2178 can can also be recorded on a digital tape recorder 2182. The one from the chart recorder 2180 seismic intercepts recorded on the monitor correspond to those previously in use have been achieved using several different seismic cables. Now you can different types of explorations by using the special cable and the special control sound 2172 as well as the group form circuits 2178 can be realized without the seismic cables

\ ^r i need to be physically shifted two miles in length.

The output from the control unit 2172 is also given to a second group form device 2184, which is also referred to as the beam steering device. If desired, the beam steering device 2184 can be operated directly from the control unit 2172. However, it is often desirable to have only the seismic information from the control unit 2172 to the recorder 2186 high speed and high Record density and use them at a later time using the beam steering device 2184 of the additional tape device 2188. The recorders 2186 and 2188 can e.g. B. VCR be. The output from the beam steering device 2184 can be sent to the conventional digital tape recorder 2190 and a normal seismic data processing device 2192 are abandoned, to create the final high resolution cross-section 2176 using a conventional seismic

J5 see curve recorder 2194 to create. A normal one Shift correction for the group signals c can be achieved by the processing means 2192. On the other hand, a normal displacement correction can also be carried out within the beam steering device 2184 (see below).

As discussed in detail above, the cable 2152 of Figure 31, as shown in Figure 32, may be a Row of transmitter / receiver units within connector modules c 2164a, 21646, 2164c, ...

2164/7, so that Fig. 32 essentially corresponds to the upper part of FIG. 17 at this point however, it is repeated in order to improve the understanding of the explanation of the beam steering.

The two broadband transmission links connect the control unit 2172 (Fig. 32) to the transceiver units; the first broadband transmission link is the data connection 1014, the second is the control and interrogation connection 1016, as in FIG Fig.32, which also shows that each transmitter-receiver unit a query network 116 and a repeater network 114

As mentioned above, the 50 cable sections 2156a, 21566.2156c; ..., 2156n of FIG. 31 uniform distributes a number of sensors along its length

Μ on, each with three sensors to one elementary Sensor unit are connected. Three of the ten elementary seismic sensor units 21, which each cable section are assigned are in Fi g. 32 seismic images are shown Analog signals from each of the seismic sensor

H5 units 21 are transmitted in multiplex mode and in the repeater converter circuit 114, the transceiver unit converted to digital format and by a second multiplication step the width

band transmission link 1014 abandoned as explained above. The timing of the transmission of the signals transmitted in multiplex mode is controlled by the interrogation signals are controlled, which are applied to the interrogation control unit 116 on the transmission link 1016 as described in detail above.

FIG. 33 shows part of the block image of FIG 31 in detail and corresponds in some respects Fig. 21. In Fig. 33, the group forming device 2178 is in the large block shown in phantom and which bears the reference number 2178, and corresponds to the group forming device 1030 of FIG. 17. The system controller 2172 of FIG. 31 is shown in FIG. 33 represented by blocks 2212 and 2214. data from of the transmission connection 1014 of the cable 2056 are in the data recording and processing device 2214 recorded, which corresponds to the data recording device 1028 of FIG. 17, which contains the data words the Gruppenformeinrichiung 2178 under the control of the main control unit 2212 gives up its counterpart in the main controller 1019 of FIG. The recording and processing device 2214 converts the transmitted seismic digital data words from the data channel 1014 into binary numbers and effects a format control of these data in binary numbers with fixed commas, which are suitable for processing in the digital group form facility 2178. Simultaneously with the recording of the data information on the recording device 2214, a memory address and timing circuit 2216 (corresponding to 1017 in FIG. 21) is put into operation to restore the original Identify the location and number of the seismic sensor units and record them of the seismic Assign information. The seismic data from the processing device 2214 is transferred to the allocation memory 2218 (corresponding to 1083 in Fig. 21), where they are rearranged and according to instructions written into the data channel sequence from the write control circuit 2230 (corresponding to 1037 in FIG. 21) will. The allocation memory 2218 transfers the seismic information to the data channel sampling memory 2222 (corresponding to memory 1047 in FIG. 21). The data channels are from 1 to 500 numbered, starting with the elementary seismic sensor unit 21a, that of the system control unit is closest, while the most distant seismic sensor unit is indicated as 21 π (see Fig. 32). This numbering scheme for the sensor units is also shown in FIG. The assignment step serves to identify the different consequences of the connection of the seismic data signal Äüf the file connection 10i4, as above was explained. The detailed internal control of the group forming device 2178 is carried out by the control unit 2224 reached (see control unit 1081 in Fig. 21). The control unit 2224 is the group control read-only memory 2226 associated with the memory 1067 in FIG. 21 corresponds to information related to the desired ones Group combinations of the seismic signals from the 500 elementary seismic sensor units will This group information is introduced into the control read-only memory 2226 can, for example, form a group like the one shown in FIG. This would be a group of ten elements with changed evaluation coefficients, as described above. The desired group rating coefficients are in the group form device 2178, in particular in the read-only memory 2228 introduced (corresponding to memory 1055 of FIG. 21).

In forming the combinations of seismic values necessary to form the assessed group the data stored in the memory 2222 are stored in the read-only memory 2228 depending on Coefficients in multipliers 2230 and 2232 bcwertei, and the elements of each group are then added in adders 2234 and 2236, whereby these components with 1047,

IU 1055,1053; i. 10536,1064a and 10646 are identified. It is of course also a read control circuit 2238 (corresponding to 1049 in FIG. 21) for time-controlled output of seismic data from memory 2222 is provided. The sums of seismic data that each group are temporarily stored in registers 2240 and 2242 (corresponding to 1065,1Ö65Ö in FIG. 2i). The dual channels that make up multipliers 2230, adders 2234 and register 2240, and multipliers 2232, which include adders 2236 and register 2242, are used to create overlapping groups, the seismic data from a single elementary sensor unit in two different groups include, with optional different evaluation of the seismic information from a single one As it is used in different groups. From the output registers 2240 and 2242 the group signals are stored in the output memory 2224 (corresponding to 1080 in Fig. 21), of which the format control device 2246 and

the recording device 2248 are given up (cf. the circuits 1032 and 1034 according to FIG. 21). As in 31, a real-time recorder 2180 can be used with be connected to the output of the format control device 2246. On the other hand, the chart recorder can 2180 can be stored on tapes whose data is recorded on recorder 2248.

According to FIG. 31, the group format control 2184 for the beam alignment is in certain respects similar to the group format control 2178 of FIG. 33, but also has the additional essential property of selecting group signal elements from different arrival times at the various sensor units.
The group format control 2184 (No. 2) according to FIG. 31 is in block diagram form in FIG. 34 and their operation will be described below in connection with the diagram of FIG. 35 explains in FIG. 34, the high speed, high density recorder 2128 is shown on the far left and the main control circuit, shown as block 2252, controls all functions in the beam steering device.

within the beam steering device 2184, the high capacity of the matrix input memory 2254 provides one the main differences compared to the group format control 2178. Instead of a memory, The matrix memory stores a single value of the seismic data from each of the 500 channels 2254 data words representing 128 values of seismic information from each of the 500 channels. Of the For example, memory 2254 may be core memory. The beam steering device 2184 according to FIG. 34 points the group read-only memory 2256, the channel coefficient memory 2258, the delay selection and processing means 2260 and the special data processing circuit 2262. Additionally contains the group molding facility the input and output buffer circuits 2264 and 2266.

In operation, the group molding device combines

according to FIG. 34 selectively a large number of seismic data input signals to form groups that continuously change toward maximum signal pickup. This change in direction is intended to accommodate the changes in the angle θ , which is explained in connection with FIG. 23. If signals from successive deeper boundary layers are expected to be reflected along the seismic segment corresponding to line 2075 in FIG. 23 corresponds. In order to direct the groups, the delays along the individual channels of seismic information that are being combined must be changed as successive full cycles of group exit formation are completed during successive one millisecond periods. This is accomplished in 2260 (Fig.34) through the Verzögerungsauswähleinrichtung which outputs an address information in the mass storage 2254 to seismic data from each channel from the memory 2254 to make, which are delayed with respect to seismic data from adjacent channels in the right way.

The operation of the beam steering device 2184 is explained below from certain other points of view in order to more clearly express its operation.

In Fig. 35, an embodiment is shown in which a recording vehicle 10 is shown to the right and the cable 2056 extends to the left. The 500 elementary seismic sensor units (each having three spaced detectors) positioned along the length of the cable are represented by numbered dots drawn along the length of the cable 2056. The first eight sensor units, which are arranged in the first cable section, are shown in FIG. 35 between point 2302 and point 2304. Units Nos. 251 to 270 extend from position 2306 to position 2308, and end sensor units Nos. 491 to 500 extend from position 2310 to position 2312 "is shown represents a multi-digit binary number which is stored in the large memory 2254 according to FIG. 34. In the matrix 2254 of FIG. 35, data which are recorded by certain channels are below the associated numbered sensor unit and the data taken at successive time intervals of one millisecond from a particular channel are arranged along a vertical line, the time intervals being indicated at the edge of the right-hand side in Fig. 35. During a time interval of 1 msec, the entire 500 channels corresponding to the 500 seismic sensor units along the cable are interrogated and the resulting seismic data is stored in memory 2254. If continued As the time cycle progresses, old data is deleted from memory 2254 and new, updated information is read in again. However, a “time window” or cycle duration interval of 128 msec corresponding to 128 tests from each of the 500 seismic sensor units is stored in memory 2254. This enables the combination in the group former 2184 of seismic data from the sensor components to be grouped with the reliable time lag for taking the tests up to 128 msec

To give a specific example of how the system of FIG. 34 working in practice, identified the diagram according to FIG. 35 the storage location for three overlapping signal groups through the lines 2314, 2316 and 2318, which extend diagonally across the storage bowel surface 2254 'in Fig. 35. ) ede of these si-

^r ) signal group has signals from eight monitoring units (each of which has three sensors), as in I * i g. 27 shown. The example is based on a distance χ (cf. Fig. 29) corresponding to the 251st Sensorcinhcit.dio at a distance of 1800 m from the launch site, usually in the vicinity of a lind of the cable. It is also assumed that the time / = 1 second and that the seismic velocity is 2100 in per second. The distance dx between the nerve units is 6 m

i. ^r · case of the present example. If you put these values in the formula (O), al = 2.45 msec. This is the desired delay between seismic signals emanating from neighboring elementary seismic sensor units which are connected to the group at a distance of 6 m. During the execution, as can be seen in connection with the line 2314 in Fig. 35, the first sample from the sensor unit No. 251 taken at / equal to 1000 seconds. The second group signal is output from the sensor unit No. 252 taken at / equal to 1.002 seconds. Similarly, the third test from sensor unit No. 253 taken at time t = 1.005 seconds. The remaining five units of the eight units tested in this way are those above

jo of the points appear along line 2314, ie up to the 258th unit, which is checked at time t equal to 1.017 seconds. These selected delays correspond to the desired 2.45 msec per channel and result in the in-phase summation of the reflective

J5 generated seismic signals.

In Fig. 35, lines 2316 and 2318 represent overlapping groups. In particular, the group indicated by line 2316 has elementary seismic sensor units no. 256 to 262, and the group represented by line 2318, sensor units No. 261 to 268. The group represented by line 2316 begins at a distance of 1830 m from the launch site, and the array shown by line 2318 begins at a distance of 1,860 m from the launch site. Using the formula (O), Δι is 2.49 and 2.52 msec for these two groups, the time ι being 1000 sec. The desired 2.49 msec delay difference per channel for the group according to line 2316 results

so the same scheme of relative delays for A'in ι; _n ; _n «ic ..,;, * rr.r- Al ™ /": »·« »« .- »<> Aar- ι;«; «ο ^ ιλ rv« uiv ι ~ ιΐιιιν fc ^ riw vTiv im uiv > _ # iuppv uvi c_.iiiiv «~» ar. i ^ iv group, which is represented by the line 2318, has, however, a much greater difference in delay between the channels, so that the fourth element of the group from the memory slot corresponding to a period of time / equal to 1.008 instead of 1.007 see lake is selected as in the case of the group corresponding to lines 2314 and 2316th Similarly, the sixth and eighth interrogations at timings carried 1.013

ω and 1.018 seconds instead of 1.012 and 1.017 seconds taken for the groups corresponding to lines 2314 and 2316. This increase in the desired delay between samples that are combined to give an in-phase summation,

h5 would of course be used in the case of groups further from are away from the launch site, and are expected to have a larger angle of the impacting seismic waves. In general, for each group in the longitudinal direction

the stored seismic inquiries can be selected depending on the formula (O).

Groups that include the first .Sensoreinheilen, which are closest to the launch site, take in the case of FIG. 35 signals along paths that are largely oriented perpendicular to the cable and therefore do not require a large delay between the channels to be combined. On the other hand, the cable run the incoming reflections at a smaller angle than the ^r in de middle of the cable for the end group on Linde and therefore require a much greater delay between adjacent channels, as the signal information is combined. In addition, the desired delays between the channels change over time and are reduced with increasing time, since reflections from progressively delivering geological interfaces arrive at the groups with an almost vertical angle of incidence. From a mathematical point of view, the groups can be expressed by equations of the following form:

Yj

Yf

1,000

r v25i

(Q)

y258 ^{1 r} 1.017

(R)

wherein a V / a G ruppenabfragung J ^lal G roup at time /, Yf, + _ml), a sampling of the K ^'c "input channel at the time corresponding to ι, wherein (the inclination ζ multiplied increases m with the check number, and Ci of / '■ · is the coefficient switched on an input channel for the output of the / "'" groups. Equation (Q) applies to short groups, e.g., the groups of eight elements represented by lines 2314, 2316 and 2318 in Fig. 35, since equation (Q) assumes that the slope ζ is constant and this assumption is only true for short groups.

When evaluating equations (Q), (R) by computer, it should be noted that the successive Group signal outputs are a combination of signals from eight neighboring sensor units that are obtained at different, separate sampling intervals, which are chosen to be the The slope of the delay versus the distance of the incoming seismic waves approach. In the present This inclination is 2.54 msec for the sensor unit distance of 6 m selected samples offset from one another by two or three milliseconds.

For the group with ten sensor units according to FIG. 27 are the ten coefficients 1,2,3,4,5,5,4,3,2,1. Thus, for example, for the eighth of the ten coefficients in a group, samples to be included according to FIG. 27C ₈ / = 3.

On the other hand, and for other explorations, a rating can be applied to all samples. Additionally can of course use a larger or smaller number of channels in the formation of group signals be used. However, there are typically between eight and 32 elementary seismic sensor units provided in each group. There is thus the possibility of processing data using of groups being steered in the expected direction of arrival by seismic signals.

and then processing the data to direct the groups in modified directions that appear on the special geological conditions are eliminated, so that a better "picture" of what is to be explored Terrain is preserved without requiring additional on-site work

In connection with marine seismic systems, the seismic pulse is normally initiated on the ship when the cable is towed behind the ship. The beam steering device accordingly shapes the groups in such a way that their direction of maximum uptake is directed towards the ship and downwards and points further and further downwards with increasing time when seismic reflections return from deeper geological boundary layers. Similarly, in connection with land explorations where the seismic pulses originate either at the end of the seismic cable or near the center of the cable, the arrays are initially aimed at the expected reflection points of the seismic pulse from horizontal geological boundary layers. It should be noted that for normal correction, this may be performed within beam steering device 2184 rather than processing means 2192 if necessary. This is discussed in connection with FIGS. 34 and 35 is achieved by selecting seismic group samples from memory 2254 which are laterally shifted as a grouping from the samples included in adjacent groups. In Fig. 35 this would correspond in a quantitative way to the shifting of the line 2316 downwards, ie later in time, in the field 2254 ', so that the corresponding group is shifted with the correct time; thereby, at any given instant in time, the group signals from the 5 groups represented by lines 2314 and 2316 would represent both reflections from the same depth. Of course, memory 2254 would have to be increased in capacity to accommodate the large delays required. In this way, normal correction in addition to the group formation in the beam steering device 2184 can be achieved. To continue the description of the seismic data processing device, reference is made below to FIG. 36, which is a simplified schematic representation of the arrangement according to FIG. Thus, FIG. 14 shows the multiplexer 122 with a plurality of receiving channels Cu C?. · · ■ C _n , all of which are connected to multiplexer multiplexer 312 via DC coupling capacitor 123, resistors 315 and switches 316. The signal reception channels are coupled to seismic sensors 21. Each resistor in conjunction with its capacitor 123 forms a high pass /? C filter for its channel. The filter removes the DC components of the incoming analog signals. The switches 316 are fast responding FET switches of known construction. The output from the multiplexer 122 on the multiple line 312 is connected to a signal processing and amplification network (SCAN) 3011, which schematically represents the circuit arrangement shown in FIG. 16 and thus, for example, has the amplifier 320 'and the test and hold circuit 322' Network forms and amplifies the tested analog signals before they are sent to an evaluation device 3033. The network 3011 may have a fixed gain buffer amplifier, a test and hold circuit and other Strnmi · «;« · *., .- α., Π, «

preparation of a signal sample prior to transmission to the evaluation device 3033, the evaluation device in practice being the amplification system 124 and the analog-digital converter 126 of the above description one of the two polarities on earth have kana and the internally generated interference voltage V ₂ on network 3011 occurs at the output and is algebraically added to the voltage Vi. If the voltage amplitudes of the incoming desired signals can be compared with the interference voltages V ₁ +> V ₂ , the interference signal ratio becomes too high. In seismics, a track that is too affected by noise signals has to be erased frequently, as a result of which valuable seismic information is lost.

The interference or stray voltages Vi + V ₂ have various causes, z. B. thermoelectric influences. Peltier effects, displacement drifts of the amplifier lines in network 3011, etc. Each of the FET switches 316 that is used in multiplexer 122 induces the interference voltage Vi on a capacitor 123. It is known that FET switches have feedthrough capacitors and bleeder resistors between their control and switch terminals (not shown) need. The control terminals of each FET switch are acted upon by a relatively large control pulse, which is supplied by the network 3011, on a control line 3021.This control pulse reaches each DC decoupling capacitor 123 via the feed-through capacitor and the leakage resistance of the associated FET switch 316.

The capacitors 123, which are feed-through capacitors and bleeder resistors, are the FET switches each identical. Therefore, the control voltages across the capacitors 123 are approximately the same.

According to FIG. 37, one of the input channels to the multiplexer 122 is grounded in accordance with an improved circuit arrangement. This channel, referred to as the CO or "test" channel, is similar in every respect to the multiplier input channels Ci-C _n - ι which receive signals. where η is the number of channels, except that the input connection to the channel CO is connected to ground, so that no external signals can be given to the test channel CO. The test channel has a capacitor 123 '. which has the same capacitance value as the capacitors 123. A multiplexer switch 3023 is assigned to the capacitor 123 '.

The test and hold (SM) network is between the network 3011 and the evaluation device 3033

1050 (Fig. 18) switched on, which has the series capacitor

1051 and the normally open shunt FET switch 1052, which is tied to ground, as in the Explanation of Fig. 18 mentioned, has.

The output of the multiplexer 122 to the trunk line 312 is connected to the network 3011 which includes the amplifier 142 with a gain of ONE (FIG. 18), the output of which is connected to the signal test and hold circuit 1044 (FIG. 18) shown in FIG not shown is connected.

The state control device 132 controls all operative networks of the switching arrangement according to I · 'i g. 3021. 37 via the control lines example, the controller 132 sequentially switches the Mulliplexcrkanälc GrC _n .. ι over a scanning cycle, and controls the Signalauswcrtvorrichtung 3033 that the amplification system 124 has which is coupled to the analog-digital converter 126 in the manner described above. The converter 126 converts the multiplexed analog signals from the channels Ci-C _n - ι in

s corresponding digital numbers around. Other networks related to the feature discussed here are of no importance are from FIG. 37 omitted for a better overview. In the operation of the system of FIG. 37, at the beginning

ίο a multiplexer sampling cycle of the multiplexer 122 on the test channel CO is reset, at which point switch 3023 and another switch 3026 closed. The stray voltage Vi, which is generated at the capacitor 123 ', is algebraically the stray voltage V ₂ that arises on network 3011 is added. The voltage Vi + V> combined in this way is transmitted to a capacitor 3025 so that a test voltage V is generated there which, when the switch 3026 is open, has the opposite polarity did to the voltage Vi -f V ₂ has Every time the multiplexer is reset to the test channel CO, the test and hold network 3024 receives the stray voltages from the Tcstkar i \ CO and from the network 3011. Subsequently, the switches 3023 remain and 3026 ge opens, while the multiplexer 122 sequentially the active. Signals receiving channels Ci, C ₂ , .., C _n - ι scanned.

When the capacitors 123 and 123 'have the same capacitance values and when the total amplifier If the network 3011 remains constant, V = V, + V ₂ applies. When the multiplexer 122 scans the channels Ci-C ",, _ ι, each channel at the output of the network 3011 has a signal voltage K- ,, as well as the scattered noise voltage Vi + V ₂ , which successively and

J5 is algebraically added to the test voltage V obtained from capacitor 3025 according to the following equation:

ν, + V ₂ + (-v; = v,. ".

This shows that every stray voltage V _t + V ₂ from every channel receiving signals is largely deleted by the test voltage V.

Fig. 38 shows the principle of the deletion of Slreu-

voltages as shown in the circuit according to FIG. 16 to be abandoned. Instead of individual resistance 315 in Fig. 37 the only resistor 315 "is used. For the reasons given above the capacitors 123 and 123 'are considerably small nercn capacitance value than the corresponding condensers Sators of the F i g. 37. Similarly, a given leakage current generates from switch 316, for example a larger voltage on the capacitors 123 or 123 'according to Fi g. 38 than the corresponding larger

Capacitors of FIG. 37.

In Fig.38 show other circuit elements that are not identical to those according to FIG. 37, but rather correspond to circuit elements of FIG Multiplcxer buffer amplifier 142, the signal test and

u) holding capacitor 1046 and buffer amplifier 1048. Aside from these minor circuit differences, the foregoing description of FIG. 37 fully applicable to Fig. 38, and the compensation voltage is generated on capacitor 1051 (which is also

b ^r > only in the more detailed circuit according to FIG. 18) in order to compensate for the current voltages appearing on the capacitors 123. To continue the description of the seismic

Data processing equipment is provided below with a detailed explanation of the amplification system variable gain in connection with Figs. 39 to 42 given.

In Fig. 39 shows the left side of the analog-digital acquisition system including the multiplexer 122 with signal input channels C1. C ₂ , .. ^ C _n , where the output of the multiplexer tuf of the multiple line 312 is connected to the non-inverting: input of a buffer amplifier 320 with the amplification factor ONE , which can be an operational amplifier, the output of which is connected to the test and Hold circuit 322 is connected; these circuit components have been explained in detail above, in particular in connection with FIG.

The amplification system 124 with variable amplification factor has an input connection 3130 and an output connection 3132, and basically consists of at least two, better four amplifiers with a stepwise variable amplification factor, ie amplifier stage η A ;, A ₂ , ..., A _n , which in Are connected in a cascade. Each amplifier, ie each stage, has a pair of input connections 3133, 3134 and an output connection 3135 (FIG. 40). The non-inverting input 3133 to the first amplifier stage A \ is connected to the input terminal 3130, which receives the output signal from the test and hold circuit 322. The output voltage of the last amplifier stage A _n at the output terminal 3132 is given to a signal evaluation device, which is the analog-digital converter 126 in the system described here, as is the comparison device 3138. The gain factor a set, ie set, by two states, namely on one. Low gain state of ONE or the high gain state Gj, where G, a discrete high gain value for the / th (i = 1, 2 in)

Amplifier is.

The state control unit 132 mentioned above in connection with FIG. 14 is between the Switches 316 and 326 via control manifold 341 switched on, which has a plurality of control lines. The controller 132 sequentially switches the signal input channels Ci-C, via a multiplexer sampling cycle, as described above.

A variable reference decoder 3144 and the window comparison device 3138 are assigned to the state control device 132. Gain control lines 3150 and control lines for noise signal suppression 3160 connect the state control device 132 to one of the amplifier stages A 1 to A 1. For the sake of simplicity, only one gain control line 3150 and one control line 3160 for noise signal suppression are shown in FIG. 39, but there are as many control lines as there are amplifier stages.

In one embodiment, the state controller 132 is a synchronous, programmable counter, e.g. B. of type 74 S 161 with integrated circuit. The reference decoder 3144 is a digilal to analog converter, e.g. of the type MC 1403 L The comparison device 3138 can be a voltage comparator of the type LM 311 and the amplifiers Ai to A, "are operational amplifiers with high input impedance, e.g. B. of the type LF 156.

Each of the amplifiers Λ ι to A _n has a control circuit for the gain factor and a circuit for Noise signa-suppression on, both are in.individual shown in Fig. 40. The control circuit has a voltage supply network, which is represented by resistors 3170, 3172, FET switch 3174,3176 and the special amplifier

kungsstcuerleitung 3150 is formed during the process of Setting the gain factor when switch 3176 is closed and switch 3174 is open, the output signal of the amplifier is fed back from output 3135 to the inverting input 3134

pelt, which places the amplifier in its low gain state equal to EWVS. When switch 3174 is closed and Schakäir 3176 is open, the switch will be in its state high gain (e.g. Gi for the amplifier

is Ai) because resistor 3170 is then in the amplifier's feedback loop. The desired degree of reinforcement will depend on a The control signal from the control unit 132 is set via the control line 3150, which is based on the stronger level, e.g. B. A _x in Fig. 40 refers.

The noise reduction circuit includes FET switches 3182, 3184, 3186, a capacitor 3188 and an interfering signal control line 3160. When switch 3182 is closed, switches 3184 and 3186 opened. When correcting the set values of each amplifier, the control unit 132 sends in Signal via control line 3150 to close switch 3176 and open switch 3174, whereby each amplifier is in the state with amplification. kungsfaklor EINS is brought. At the same time, the control unit 132 disconnects the input connection 3130 to the amplification system 124 by opening the switch 3182 and establishes the connection between the connection by closing the switch 3184 (FIGS. 40 and 41).

J5 connection point 3190 and the output terminal 3135 of the Amplifier. Input terminal 3133 to the amplifier is grounded by closing switch 3186. The switches 3182,3184 and 3186 are activated by a Signal actuated, which is sent on control line 3160

comes. Any DC disturbance ("skew") will then appear on the amplifier's output terminal 3135. A capacitor 3188, which is connected in the manner shown, is connected to its plates 3188a, 31886 in the manner shown in FIG. 42 specified displacement voltage + V

charged, which occurs at the input terminal 3133. When the correction is done, that closes Control unit 132 switches 3182 and opens switches 3184 and 3186 with the aid of a second signal the control line 3160 so that the input port 3130 reconnected to amplifier system 124 and the amplifiers will be switched back to normal operation.

The charge voltage + V on capacitor 3188 is now algebraic with the incoming signal Vi _n is added and is completely canceled by the correction or shift voltage + V impressed on the amplifier, as in FIG. 42 shown. The output signal of the amplifier is thus free of DC voltage fluctuations, regardless of the gain factor,

t> o to which the amplifier has been set. The factors that determine how often it is necessary to switch to correction mode depend on the speed at which the zero point values are drifting and on the Wen the input impedance of the amplifier.

h5 When operating with a variable gain factor the amplification factor determination cycle begins for each channel (e.g. channel Ci) by placing all amplifiers on the gain factor I. The

81 82

Stand-alone device 132 produces a sequence of digital train voltage V _AI corresponding to amplifier A ₁ . ten that have a corresponding sequence of variables. If the comparison is negative, i. h if the absolute reference voltage represent steps. The digital values of V ₀ V "is value smaller than, that gives Vergleichseinwerden in corresponding discrete reference voltages direction 3138 a command to the control unit 132. DA V _R by the reference decoder 3144 converts the 5 with the normally closed switch 3176 ge reference voltages can by the sequence opens and the normally open switch 3174 is closed (Fig. 40). The amplifier Λ now has the

Vri - VVGi, Ve ₂ - WG ₂ , ..., V « _m - V ₈ G _1n Setting with a high gain factor. The signal under test generated by test and hold circuit 322

are graded, where Gi, G ₂ , .., C _n , the higher io is echoed, values for the amplification factor of the amplifiers Ai, are again amplified by the binary system 124 as the amplification factor changes, where- A ₂ , ..- A _n , and V _{B are} a base voltage equal to that when amplifier A _{x is set} to its high preselected fraction of the full voltage of the ana-gain setting and amplifier log-to-digital converter 126 is gain- A ₂ - / 4 ₄ on their settings for gain ren Gi, Gi, etc. are proportional to a chosen Po- is remain ONE. If the new value | K ₀ 1 less than V « ₂ is tenz an equal number base, z. B. two. The suffering. If the result of this second comparison is again the same for each amplifier. Which is negative, the comparison device 3138 outputs a variable reference voltage step Vk / are reversed. Command to the control unit 132 to reverse the amplifier Ai in proportional to the gain factors of the amplifier corresponding to its high gain setting. At the control unit 132 can bring 20. The checked signal is again selected by the bis to simplify the setting function of the amplifier system 124 with a changing gain factor of 1. tor, which has amplifiers A \ and A ₂ on their settings. In one embodiment, G, - 2 exp K · "9. For high gain and amplifiers Λ 3, Aa on it in a four-amplifier amplification system (m ■ = 4), ren settings gain ONE has the corresponding values high Verslärkungsfak- 25 are reinforced when the next value | V ₀ 1 <Vr _3, ie tors for the amplifiers: Gi - 256, C ₂ - 16, G ₃ - 4, though. the result of the third comparison is again nega-G _4-2 . With only four settings with high gain, control unit 132 proves that the gain factor can set the gain factor of the binary A _s (not shown) to a high gain adjustable amplification system 124. If, after the fourth comparison, it is found that it _{results from a minimum of two to 30 | V 11} 1 < Vm , then control unit 132 causes the zeroth power (ie one) to be Maximum of 2 to the A4 repeaters (which can be the amplifier A _n ) 15th power (ie 32,786) in steps of powers of 2 including a high gain setting is enough. To achieve this, only four settings are required, but if | V _n | > Vr _{becomes 4} , the controller considers 132 divorces necessary for the gain. The amplifier on gain ONE. After amplification comparisons must be carried out in such a way that the fourth comparison ends, the comparisons are that the amplifier for the highest amplification device 3138 a command to the control unit 132 is first set, and then the analog-to-digital converter 126 then the voltage Comparisons in the order of decreasing V ₀ , which are then made at the output terminal 3132 of the amplification level of the amplifier, occurs, and converts them into a digital number,
regardless of the position of the respective amplifier 40 after completion of each amplification factor in the cascade. The method of operation with the changing Vcislärkungs- cascade of four amplifiers by the control unit is explained in detail below. As a digital gain codeword, if 132 are all four amplifiers dated to gain ONE , which contains as many bits as there are steps, i. If the amplification is set, the absolute value of the output voltage will be 45 kcr in the amplification system 124. ) cdcs voltage IV ₀ j of the system, which occurs at the output terminal bit of the gain code word represents the state 3132, with the first reference voltage V _H 1 - V ₈ / - of the switch 3176. The gain code is 256 compared by the comparison device 3138. ONE when switch 3176 is open, it is ZERO, comparator 3138 sets voltage V _n when the switch is closed. Thus, in the case of is equal to and compares its absolute value with the reference 50 four amplifiers when all amplifiers are on the amplification voltage V _K \. The decision, which are set on this distortion factor ONE , which is based on the gain factor equal, is given to the control unit 132. lorcode 0000. If the overall gain factor is 64 " ¹ A If | V ₀ |> V * 1, the controller 132 causes that is, the gain factor code 0110 etc.
\ $ the amplification factor of amplifier A \ on one With four amplifiers that only make four decisions? ' Value £ WS remains. If | V ₀ 1 < V _R , sets the control request, the binary amplification system 124 supplies with '.' The device 132 sets the gain of the amplifier A \ changing gain factor, which is explained here nt to Gi, ie 256. The variable reference voltage eri Vr is ₂ , ie 2 ^r 'gain levels.
ΓΛ Vr ₃ , V _{ft4 then become} sequential with the successive values of the output voltage V _n between a relatively slow progressions have been carried out. After the progressing interrogation signal and a relatively equal one, the gain is determined by the control unit 132, a slowly progressing interrogation signal and a for the amplifier, which sends the next successively rapidly advancing command signal, namely a lower gain factor corresponding to the data signal given to the DATA signal. been explained. This Prin reference voltage, which is used for the comparison, b ^r > zip, is discussed below in connection with FIGS. 43 to has. 48 further explained, since it is generally used for the purpose of ί The comparison device 3138 thus compares the initiation of a switching process.

Output voltage | V ₀ | at connection 3132 with the fig. 43 is a schematic, simplified overall

Representation of the previously explained seismic data processing device, which the common central data processing device, ie station 2 and the large number of identical, spaced, multi-channel data acquisition devices. ie Trans- ■> dcr-Receiver units Uta, 1116, HIc, III </. which are connected in series and connected to the central station via transmission lines which have been explained above and which is shown in a simplified manner in FIG. 43 as a signal transmission connection 4016 with three channels. The distance between the transmitter-receiver units is constant and is approximately 60 to 90 m.

The central station 2 has a control unit 4018 and a recording unit 4020, which are schematic representations of the explained sound system. The simplified representation of units 4018 and 4020 is to be understood as representing the system control unit and the data receivers (block 2172 in FIG. 31), a detailed block diagram of the central station 2 being explained and illustrated above in connection with FIG. The recorder 4020 may be a magnetic tape recorder known in the art. The control unit 4018 comprises a signal transmission device, e.g. B. a clock circuit of a known type, for the transmission of the multi-state A bfragesignalc IP, / _ B. pulses 51 and 52, on preselected test signals and / or a control signal through the channels 4090 and 4091 of the Drcikanaligen signal transmission link 4016, as explained above became. jo

After each transmitter-receiver unit IHa, lliö has completed the transmission of its local data, it receives data from more distant data acquisition or transceiver units, regenerates them and transmits them to the central station 2. The J5 Data acquisition unit 11a, which is closest to station 2, thus transmits its local data first and then receives and transmits data from the remaining 99 downlink units (assuming 100 such units exist in the system). The last data acquisition unit naturally only transmits its local data.

An interrogation signal can assume one of a variety of states. The query and control signals are / .. B. square-wave pulses. The propagation speed of a pulse through the interrogation channel 4090 is different from the propagation speed of a pulse through the Stcucrkanal 4091, the interrogation channel 4090 schematically representing transmission lines IPX, IP2, IP3 , while the control channel 4091 the DATA and data connection lines in the figures . Figures 5 and 8b. In the embodiment discussed here, the transit time through the Stcucrkanal 4091 is greater than through the interrogation channel 4090.

When a data acquisition unit, e.g. B. a transceiver unit 1116, is defective, it must be shunted so that data from a more distant unit, z. B. the unit 11 Ic are transmitted, are not affected. A control pulse is transmitted from the control unit 4018 via the ω control channel 4091. With a selected unit, e.g. B. the transmitter-receiver unit 1116, the receiver pulse overtakes the interrogation pulse due to the different speeds in the channels 4090 and 409t, and coincides with it. The coincidence b ^r > of the two impulses at the Kir.heil XiXb causes the unit to be shunted.

In the F i g. 43 and 44 are the data acquisition, i.e. H.

Transceiver units HIa, HIo, 111c, UIdmit a plurality of input channels are provided, each input channel having an elementary seismic Sensor connector 21 is connected in the manner described above. Each of these units contains the signal setting logic, the multiplexer 122, the test and hold circuit 3024, the amplifiers 124 determining the gain factor, the analog-to-digital converter 126 and the output signal storage register 128. These circuit components connect the seismic sensors 21 to the signal input channels the data channel 4092 '. They can be conventional. The amplifier 124 determining the degree of amplification is expediently the binary amplifier with variable gain, as described in connection with FIGS. 39 to 42, of the one with four bits encrypted amplification factor can be set. The analog-to-digital converter 126 can for example a 12-bit converter. The output signal storage register 128 can be a conventional 16 to 20 bit serial / serial shift register be. In one embodiment, the register 128 has the capacity to hold at least 12 bits of data from the analog-to-digital converter and four gain code bits.

As described above and shown in FIG. 44, the control unit 132 is provided, which is activated by signals 51 or 52 on lines 51 or 52. Signals 51 (sampling interval interrogation pulse) or 52 (divider interrogation pulse) are generated as a function of interrogation pulses that assume either a first state or a second state. The corresponding interrogation pulses, which are generally designated by the letters "IP" and which are transmitted via channel 4090, / .. B. the connections IPt, IP2, IP3 of FIG. 5 are also denoted by 51 and 52, where 51 assumes one state (namely a certain width) and 52 another state (namely a different width). As a function of a signal 51, control device 132 resets multiplexer 122 to channel CO, the test or empty channel. In response to a signal 52 following a signal 51, the controller 132 shifts the multiplexer 122 to the first input channel in the sequence to have the test and hold circuit 3024 test a signal on the first channel. The SI pulse sets the control unit 132 in such a way that the data output is enabled as a function of 52 pulses over the duration of the sampling cycle, the sampling cycle being the multiplexer mode for testing all fourteen input channels.

If the signal sample is amplified by the setting unit 124 for the gain factor and presented to the analog-digital converter 126, the gain factor is expressed in a corresponding manner as a gain factor code with 4 bits. When the next 52 signal is received by the control unit 132 switches the multiplexer 122 to the next channel, and at the same time causes the analog-digital converter 126 to convert the signal sample set in the gain factor from the first channel into a digital number. At the beginning of the conversion cycle, the Gain code with 4 bits is transmitted in series from the gain setting unit 124 to the output register 128 via the line 3036. In the further course of the analog-to-digital conversion will be the 12 bits, which represent the digital number, in series from the analog-digial converter 126 into the output

register 128 pushed. The 12 data bits with the four gain factor code bits are stored in register 128 to form a digital data word with 16 bits accordingly the sample from the first channel combined. Four preamble bits can be added, so that one Word is made up of 20 bits.

If the conversion cycle for a channel, e.g. B. channel K, begins, the control unit 132 transfers the digital data word from the channel K 1, which was previously stored in the output register 128, to the data channel 4092 '. A counter decoder 3037 counts the bits that have been scanned in series from the register 128 and commands the controller 132 to stop transmitting the data bits when the count is complete. The data channel 4092 'of each transceiver unit 111 is normally connected to the data transmission link 4092, as can be seen from the Γ-' i g described below. 45 results. Compound 4092 of FIG. 43 and 45 corresponds to the connection Di, DZ D 3 (see above).

F i g. 45 shows further details of the data acquisition units, / .. B. Scndcr-Empfängcreinheiten UIA, Uli ", etc., including a Signalprüfeinrichtung 4038 and first and second Koinzidenzdctcktorcn 4040 and 4042, which are shown enclosed in dotted lines. Shunt switches 4044, 4046 with loss of power, a line receiver 4048, a switch 4050 for deactivating the interrogation signals and a line driver 4052 are connected in series with the interrogation channel 4090. The control channel 4091 is provided with a line receiver 4054 and a line driver 4056. The data channel 4092 has a line receiver 4058 and an OR gate with line driver 4062. The two inputs to the line driver 4062 are the inputs 4092 from downstream data acquisition units, ie transmitter / receiver units, and the input 4092 'from the local data output register 128 (see FIG. 44). The switches 4064 and 4066 have the effect that a data output via the bypass line 4068 is shunted when they are de-energized. The direction of the data flow in FIGS. 44 and 45 is opposite to that in FIGS. 43 and 46.

The signal test device 4038, which consists of a tapped delay line 4072, the AND gate 4074 and the inverter 4076, identifies the state, i.e. H. the property of an interrogation signal in in the manner described below. The interrogation signal is essentially a rectangle with a certain width. The state or the property of a pulse is defined here by its width, although with a corresponding circuit arrangement a different property, e.g. B. the pulse height than Differentiator can be used. A broad pulse is an interrogation pulse in the first state. The width of a wide pulse must be greater than the delay time of delay line 4072, however less than half of the selected query interval. An interrogation pulse in the second state must be clearly distinguishable from an interrogation pulse in the first state. Its width is less than half of a broad impulse. In the embodiment described, the delay time of the delay line is 4072 1000 nanoseconds (nsee). a wide pulse is 1200 nsee long and a narrow pulse is 400 nsee long. Additional pulse widths can used to achieve a multi-property impulse when appropriate changes can be made on the signal test logic.

In the following description of logical circuit rules c reference is made to the two states that normally occur in such logical circuits

^r > lungcn exist. These two states can be viewed as representing binary signals and they are often referred to as logical ONE and logical ZERO . Additionally, the low and high voltage states are sometimes referred to as "binary zero" and "binary

κι one "or as" false "and" true "signals or States. If in the case of an AND gate z. IJ. the two inputs to a predetermined one Voltage levels are raised (which is labeled "true"), the output changes on that as well

Γι voltage level (referred to as "true") while when one of the inputs is on a different, lower voltage level (with "false" labeled), the output of the AND gate remains at the low level (in the "wrong" state). In Similarly, in the discussion below, the two states of logic formation will be referred to as "True" and "false" states.

When the control unit 132 (I-ig.44) an interrogation pulse transmits in the first state, the pulse passes through the interrogation channel 4090, as shown in FIG. through switch 4044 to line receiver 4048, through switch 4050 to line driver 4052, the Switch 4046 to the next transmitter-receiver element. The impulse also passes through the delay

jd line 4072. At the end of the 1000 nsee the leading one appears Edge of this pulse at the output of the delay line. At this point, however, lies the sloping one Edge of the pulse at the input of the delay line. Thus both inputs of the AND gate go

r> 4074 to a high level, which generates a 200 nsec signal on the SI line that has a positive edge. The control unit 132 sets the multiplexer 122 by a signal on the line SI. The falling edge of the wide interrogation pulse generates a positive-going logic level on the line S2 as the output of the inverter 4076, namely 200 nsee after S I switched to "true" Has.

F.s it is assumed that later a narrow interrogation pulse reaches the inverter 4076 via channel 4090 to delay line 4072. Because the pulse width is too narrow to appear simultaneously at the input and output of delay line 4072 no signal generated on line S 1. However, the falling edge of the narrow pulse occurs at the output of inverter 4076 as a positive going signal on line S2. When the controller 132 is on indicating a positive going S2 signal, as mentioned above, the multiplexer 122 is on to the next The input channel is switched on and outputs a data signal via the line 4092 'to the channel 4092 and with it to the recording device 4020.

As described above, each transceiver unit Have 14 analog input channels. In order to be able to query each input channel one after the other,

bo an interrogation pulse in the first state is first transmitted by the control unit 4018. When the broad interrogation pulse S1 progresses along the interrogation channel 4090 to each transceiver unit Ilia, UXb etc. in the order, it sets the multiplexer 122 every-

b5 of the unit. This will be followed by a series of 13 Transmit query pulses S2. Each pulse in the second state switches the multiplexer 122 further, so that he in turn each of the entrance channels from the

queries elementary seismic sensor units 21 and the corresponding data signals from the Scndcr receiver units 111 is transmitted to the recording unit 4020 via the data channel 4092.

In the embodiment described, the 14 channels are checked within 1 rrucc. According to isl the interval between SS pulses 71.4 uiicc. The two-way pulse-delayed through the transmission connection 4016 between two transmitter-receiver units results in a line gap during which the data signals from the serider-receiver units III can be transmitted without interfering with one another.

The secondary sounders 4044, 4046 and 4064, 4066 are operated in a known manner by relays and are shown in Fig. 45 in their position with the power supply switched on. In the event of an energy failure in a given scanner-receiver unit switch both sets of switches so that the shunts 4068 and 4070 are connected to channels 4092 and 4090, respectively.

A transceiver unit, e.g. B. the unit 1110, can be damaged if it becomes necessary to use them to put in shunt, or you can send a further transmission eiri; end specific unit. These special functions are controlled by a control signal in the following made effective.

The total duration of the; Interrogation pulse in a remote transmitter-receiver unit depends on the delay time through the interrogation channel. The transit time to the unit π Lt is the sum of the delay lines between all preceding data acquisition units. In a similar way it is. the delay time of a control pulse through the control channel to the unit η the sum of the delays in the control channel between all preceding units which are closer to the control unit 4018 ils the unit n. Since the transit times through the two channels are different, the η-th comes Data acquisition unit a pulse advancing through the faster channel arrives a time interval (n - \) R earlier than the pulse through the slower channel, where η - 1 is the number of distances between the first η transmitter-receiver units and R of the signal propagation is the two channels between successive units. The feed cable section 17 between the central station and the first transceiver unit is dimensioned so that the delay times for both signals, namely for the command signal and the interrogation signal, through the channels 4090 and 4091 are the same. Thus, all different delays are generated in a corresponding manner in the lines between successive transmitter-receiver units

The control pulse is transmitted overtaken the interrogation pulse R later, a control impulse for the control unit 4018 - Assume daQdie pulse transit time in the control channel 4091 is greater than in the interrogation channel 4090. When an interrogation pulse from the control unit (. G Fi 43) 4018 and (n-1) at the unit n. Both the query and the control channels can have identical signal transit times. Delay lines can be inserted into one of the two channels on each transceiver unit to create a delay time difference. For example, a delay line 4078, which is shown by the box indicated by dashed lines in FIG. 45, can be inserted into the interrogation channel 4090 between the line receiver 4048 and the shutdown switch 4050. In addition, the delay line 4078 can serve as a replacement for the delay line 4072.

The first signal or pulse coincidence detector 4040 comprises a D flip-flop 4080 and a relay 4082, the assigned to switches 4064 and 4066. The switches are shown in the position that the relay is in lined electricity. The flip-flop 4080 can be one half of a positive-edge triggerable D flip-flop ίο be of the type 74 S 74. The logic level at the D input is present is transferred to the (^ output when the correct edge (i.e. the transition from one logic level to another) occurs at the clock input. The flip-flop remains in its state until it is reset. The flip-flop 4080 responds to the rising edge of a pulse.

If both a control pulse and an interrogation pulse are equally present in any state, the coincidence detector 4040 is effective for the first signal. The leading edge of an interrogation pulse sets (ie activates) the D input of the flip-flop 4080 to a logical ONE. The (^ output of flip-flop 4080 is normally "false" (logic ZERO), which energizes relay 4082 so that switches 4064 and 4066 are closed, as shown in Fig. 45. When a control pulse from the connection 4091 arrives at the clock input, while the D input shows a logical ONE , the ^ output of the flip-flop 4080 is set to logical ONE, ie it is set to "true", jo This releases the relay 4082 and causes the Switches 4064 and 4066 make contact with the shunt line 4068 because the voltage level corresponds to the logical ElNSdem value + ^.

In FIG. 46, the control unit 132 (FIG. 44) transmits an interrogation pulse via the interrogation channel 4090, which is assumed to determine the shorter transit time. The control channel 4091 is connected to the control unit 132 via a tapped delay line 4132, which has taps in order to reduce integer multiples of the delay time, e.g. B. 0, R, 2R, 3R, (n- 1) R via the tap selector 4100 to achieve.

In order to bypass the transmitter / receiver η , an interrogation pulse is first transmitted via the control unit 4018 (FIGS. 43 and 46) and then (n - I) R later a control pulse. The control pulse picks up the query pulse at the transmitter / receiver η and coincides with it, whereby the relay 4082 (Fig. 45) is de-energized; this switches switches 4064 and 4066 to bypass line 4068.

It may be desirable to prevent a request pulse from being passed on to transmitter / receiver units that are beyond the unit η. To achieve this, the control pulse is time shifted so that it follows an interrogation pulse after a delay of (n- 1) R + d , where d is the time shift. This function is performed by the second pulse coincidence detector 4042.

In the second pulse coincidence detector 4042 (FIG. 45) bo, the D input of the flip-flop 4084 is connected to a tap 4085 on the tapped delay line 4072. The delay duration between the entry of the leading edge of the pulse at tap 4085 is equal to or slightly greater than the width of the pulse, the delay duration d for tap 4085 in the embodiment described being 600nsec. When the interrogation pulse arrives, it first activates the flip-flop 4080 in pulse coincidence.

denzdetektor 4040. At a time d later (e.g. 600 nscc later) the leading edge of the pulse occurs at tap 4085 of delay line 4072. The time-shifted control pulse is too late to trigger the clock input of the flip-flop 4080; thus the pulse coincidence detector 404 does not respond. Now, however, the D input of the flip-flop 4084 is activated by the delayed interrogation pulse. Therefore, a time-shifted control pulse that arrives at the clock input of flip-flop 4084 switches flip-flop 4084 and causes the normally "true"<? Output to switch to "false" (logical ZERO). This activates a relay 4086, which opens the switch 4050, as a result of which the transmission of the interrogation pulse to units that are beyond the transmitter-receiver unit η is interrupted.

In FIG. 46, the time shift t / the control pulse is applied via a fixed delay line 4102 when the switch 4104 is in the position shown. The time delay d over delay line 4102 is the same as the time delay at tap 4085 of delay line 4072, ie 600 nsec in the illustrated embodiment.

If either flip-flop 4080 or 4084 is switched by the simultaneous presence of an interrogation pulse and a control pulse, they remain in the switched state until they are released. The flip-flops 4080 and 4084 are only enabled as a function of an interrogation pulse in the first state, ie S 1, but in the absence of a coincident control pulse when the output of the AND element 4074 switches to logic f / yVS.

In addition, it may be desirable to make certain switching sequences effective, i. H. to activate and data from a subset of successive transmitter-receiver units to be delivered from the entirety of all units are selected. These functions are achieved by using two transmission links reached with varying delays. The selected subset can also, for example only one transmitter-receiver unit or all transmitter-receiver units include. If the selected subset comprises more than one unit, is one first selected unit and a last selected unit present, with the first selected unit the central station 2 is closest.

In Fig. 47, which is similar in some respects to Fig. 13, seven transceiver lines purple to 11 \ g are shown, which are connected to the central station 2 via the transmission link 4016, which consists of three channels, namely the interrogation channel 4090, the control channel 4091 and the data channel 4092 exists. The group of FIG. 47 is reversed in direction compared to the group according to FIG. 43 and, for the sake of simplicity, the input channels 21 are not shown. 47 the double arrows on control channel 4091 indicate that the signal propagation time in the channel is greater than that through the interrogation channel 14090.

When in Fi g. 47 is the embodiment shown it is desirable to activate a sampling cycle or another switching sequence in the multiplexer!) 122 and initiate that part of the subset only of the transmitter-receiver units 111c to llle form, whereby the output of data from the corresponding input channels is only effective for this subset of units is made. Thus the units 111 ;; remain.

\\\ b, lll / 'and 111 ^ inactive. The circuit for activation, ie for making the desired subset of units effective, is shown in FIG. 48 shown.

In this Fig. 48 is the data connection circuit .ί essentially the same as that of FIG. 45th but the signal checker 4038 in FIG. 48 is around the optional delay line 4078 of FIG. 45 added. The pulse coincidence detectors 404, 4042 according to F i g. 45 are shown in FIG. 48 designed differently, so that K) greater flexibility is achieved.

In Fi g. 47, the query channel 4090 is shown as the only channel. The control channel 4091 is also represented by a single line in FIG. However, it actually consists of three redundant lines. As explained in more detail above in the illustrated embodiment, the interrogation and control channels can be twisted pairs of conductors. The pulse travel times over the conductors that represent the query and control channels can then have the same value. However, the delay line 4078 in each transceiver unit is connected in series with the interrogation channel. Thus, in the device shown, the effective speed in interrogation channel 4090 is lower than in control channel 4091. Delay line 4078 delays 2 ^r i the transit time of an interrogation pulse by a fixed time interval at each transmitter / receiver unit. The delay line 4078 has a maximum delay of 1000 nsec with taps in order to achieve shorter delays and to be able to set smaller differences in the lengths of the conductor forming the interrogation channel. The delay is 600 nsec.

In Fig. 48 a query pulse, which is transmitted from the control unit 132, runs through the line 4090, via the line receiver or buffer amplifier 4048, J5 via the shunt switch 4044 to the delay line 4078. 600 nsec later, the pulse passes through the tap 4101 to the line driver 4052 and the Transceiver unit closest to the line, ie the next transceiver unit located downward in relation to the connection, in AND gate 4103 indicates the presence of a wide 51 pulse, as in connection with AND gate 4074 described in Fig. 45. The S 1-pulse 1200 nscc is wide and the maximum delay of the delay line nsec 4078 1000, the Ausgangslcitung changes 4105 of ^AND: element 4103 in a logical ONE, as discussed above, the clock input of the D flip- Flops 4106 is triggered. When a logical ONE is present at the D input of flip-flop 4106 (from a control pulse, as will be explained below), the Q output switches to a logical ONE, whereby the output of AND gate 4108 also switches to ONE. The falling edge of the S ! Pulse therefore also generates a .92 pulse, which causes the control unit (Fig. 44) to initiate a conversion cycle. As long as the D input of the flip-flop 4106 remains at the logical E // V5, the AND element 4108 is also switched on . Conversely, if a logic ZERO occurs at the D input of the flip-flop 4106, the output of S2 pulses is blocked via the AND gate 4108 and the circuit according to FIG. 44 b5 is not activated.

Control pulses that correspond to the DATA pulses described above (DATA query) are transmitted in parallel via the triple redundant control channel 4091

transfer. The D / 4TE7V pulses are received via the line receivers 4112, 4112 ', 4112 "and transmitted to a further majority selection circuit 4114. The circuit 4114 consists of AND gates 4116, 4116', 4116" and the OR gate 4118. A DA A T £ 7V pulse, which is present on any two of the three lines CON 2 and CON 3, which are shown schematically by the DA TEN connection in Fig. 5, causes the output of the OR gate 4118 to be a logical ONE is, the D input of the flip-flop 4106 is also set to the ONE , so that the AND gate 4108 becomes effective. Thus, the simultaneous presence of an S1 pulse from the AND gate 4103 and a ΟΛΓΕ / V pulse from any two of the three lines CON I, CON 2 and CON 3 generates a single signal that the data output from the output register 132 (F i g . 44) is made effective in response to subsequent S2 pulses received during the remainder of the sampling cycle. The system remains in effect as long as a DATA pulse is present every time an SI pulse is received. The DATA pulses arrive from any particular transceiver unit via line drivers 4126, 4126 ', 4126 "to the more distant units.

A desired switching effect in a selected transmitter-receiver unit can be initiated by sending a D-4.TEN sleuer pulse over a single control line, e.g. B. only the line CON I is sent. If a D / 47E7V pulse is on only one line, e.g. B. the line CON X occurs, the output of the majority voting circuit 4114 is a logical ZERO. The output from the inverter is therefore a logical ONE, whereby the AND gate 4122 becomes effective. If an S 1 pulse is received over the single line CON X at the same time as the DA TEN pulse, the output of AND gate 4122 becomes "true", which sets the clock input of flip-flop 4124. Since the D input of the flip-flop 4124 is also "true" because the D / 47 "£ AMpulse is present on the line CON X , the (^ output becomes" true ", which generates a Ci pulse. For example, a C! Control pulse can be used to counteract the data bypass relay 4082 '. The bypass circuit 4082' is normally held in the position shown unless a C1 pulse or a power failure (PF) de-energizes the relay, over the NOR gate 4142, whereby data is diverted from a more distant data acquisition unit shunted around the relevant transceiver unit considered in this explanation can be taken from the circuit in Fig. 48. DATEW pulses, which are supplied by via the individual lines CON 2 or CON3 , generate control signals C2, C3 in a similar manner so that other selected control functions ctions can be carried out. The width of a DA TE / V pulse which is used to activate a desired switching effect in a selected unit is half the width of an S 1 interrogation pulse, ie approximately 600 nsec

In Fig. 47, which in some respects of FIG. 13, a special effect is shown which is based on the fact that the activation of one or more transceiver units requires the simultaneous presence of a pulse pulse and a DATA pulse at each of the units. In Fig. 47 a plurality of data acquisition units, ie transmitter / receiver units 11 a to 11 a, are arranged away from the central station 2. It is believed that it is desirable to activate only the three consecutive units 111c to IHc, but not others.

An SI pulse is transmitted from the central station 2 to each unit 111 one after the other via the interrogation channel. Let the moment of arrival of S at the unit lilac be denoted by f., = 0. The arrival time of SI at unit 11 Xb is then tb - 856.8 nsec. The pulse delay between the units lila and XXXb is made up of the cable delay and the delay of 600 nsec in delay line 4078 (Fig. 48). The length of the cable between the two units is 60 m; the pulse transit time is 391.5 m / nsec. Since the cable delay is 256.8 nsec and the line delay time is 600 nsec, the total delay is 856.8 nsec. Thus, the arrival time of S1 at the unit IHcZ ₁ = 1713.6 nsec, etc., as shown in Fig. 47. The six timing control lines in FIG. 47, labeled IPA to IPF , represent the position of the same S1 interrogation pulse in relation to each of the transmitter / receiver units lila to XXXf at the end of each 856.8 nsec interrogation pulse transit time interval.

Some time after the transmission of an S1 pulse through the interrogation channel 4090, a DATENAmpuh is transmitted through the control channel 4091. The signal transit time in the twisted wire pairs of the query and control channels 4090 and 4091 are the same. Because of the 600 nsec delay line 4078 in each transceiver unit, the effective S 1 pulse rate is less than the control pulse rate because there are no corresponding delay lines in the control channel. In another embodiment, the cable transit times of the two channels can of course be chosen so that the desired delays occur in the channels themselves. The taps on the delay line 4078 then only serve to compensate for slight differences in the cable lengths.

In FIG. 47, a D-47 "£ N pulse, which was transmitted 1200 nsec after the transmission of a corresponding SI pulse, takes over the SI pulse at the third unit, ie at the transmitter / receiver unit HIc. The six timing control lines, the with DATA A

so until DATA is labeled F indicate the position of a DATA pulse with respect to the S 1 pulse at the end of each 356.8 iisec interrogation pulse travel time interval. If a SI pulse arrives at the unit 111 a, there is no effect on this unit,

because the DATE / V pulse lags behind the S1 pulse by 1200 nsec. At the unit 1116, the DATENAm puh 600nsec is behind the SI pulse, so that again no change occurs at the unit 1116. The DA TENAmpuh picks up the SI pulse at the unit HIc, so that the data processing circuit of the unit 111c becomes effective. At the unit 111 d, the leading edge of the D / ITETV pulse leads the S1 pulse by 600 nsec. Due to the width of the DA TEW pulse, however, a control signal is available to reduce the

Unit! Ineffective. Even though the leading edge of the DA TEN pulse is 1200 nsec before the SI pulse, the falling edge has not yet passed the SI pulse: thus it becomes the finhpit

effective. At the point in time at which the S 1 pulse arrives at the unit 11 l /, the falling edge of the DATEN pulse finally leads the 5! Pulse. Therefore, the transceiver unit 111 / ° and all subsequent units downward with respect to the connection are ineffective. All units that are activated by coincident 51 and ITEA pulses remain activated over an entire scanning cycle. This means that they respond to all subsequent, incoming 52 pulses over the remainder of the scanning cycle. The desired delays are applied via the tapped delay line 4132 (Figs. 46 and 47). The width of Weines DA TEN impulse is

W = (L-I) - DLY dt.

Number of transceiver units that are activated, artificial delay duration (delay line 4078) and small time increments of arbitrary length to allow small propagation time differences.

In the example according to FIG. 47 is the width of the D / ITE / V pulse

W = (3-1) * 600+ 300 = UOOnsec.

The width of the control pulse can be changed with the help of the pulse width setting circuit 4130 (Fig. 47), which is connected to the control unit 4018 in the central station 2. The pulse width series circuit may be a monostable multivibrator, for example of the 74 121 type. The pulse width setting is changed by an RC feedback loop connected to the control inputs of the monostable circuitry

The initial delay time ID given to the DAR £ 7V pulse through delay line 4132 is

/ D- M- DLY,

where M is the number of intermediate transceiver units that are to be skipped between the central station 2 and the first active transceiver unit (FIG. 47).

As stated above, a CON 1 pulse, when in coincidence with a 51 pulse, is used to bypass data to a selected transceiver unit. The delay BD imparted to the CON 1 pulse over delay line 4132 relative to an associated 51 pulse is

BD-K- DLY,

where AC is the number of transceiver units, which lie between the central station and the selected transceiver unit.

The triple redundant control lines 4091 according to FIG. 48 are shown as individual lines in FIGS. 43 to 47 and in FIGS. 5 and 8b and denoted by DATA in order to simplify the drawing. From the above description and the formulas it follows that by suitable selection of control pulse width and control pulse delay with respect to a 51 pulse, any desired subset of successive transmitter-receiver units can be made effective. For example, the three units IHa. 1116 and IHc activated For the second scan, the units 1116. IHc and IHc / are activated, the third ίο scan can include the unit HIc, IHc / and 11 Ie, etc.

Using this so-called roll-off technique, the control pulse width for the first scan is (3 - 1) * 600 + 300 = 1500 nsec. The initial delay is zero because there are no intermediate transceiver units between the unit lila and the central station 2. In the next scan, the control pulse width remains the same, but the initial delay is 600 nsec because a unit, namely the one that complies with purple, is between the first selected unit 1116 and central station 2, and so on.

When conducting a seismic survey, of course, "one recording cycle of an acoustic wave is generated for many seconds and seismic reflection data are recorded. Corresponding many consecutive scans are performed using the same subset of data acquisition units use. For a recording jo of six seconds, sampling intervals of 1 msec 6000 scans performed. After the first recording cycle, the system will move on to the next Subset of data acquisition units »scrolled forward«, by shifting the delay and J5 it becomes a new recording cycle of 6000 samples began.

As mentioned above, there is a 51 pulse from the central station transmitted to the data acquisition units once per millisecond, so that a test interval of 1 msec is set. If 14 input channels CO to C13 with elementary seismic sensor units 21 are present, a series of 13,52 pulses will be generated are transmitted, the pulses being generated at intervals of 71.4 (isec. As explained above, is the frequency of the transmitted interrogation pulses related to the frequency of the reflected seismic signals. For signals of high frequency in the order of 200 Hz, the sampling interval should be 0.5 to 1 msec (2000 up to 1000 samples per second). For seismic Signals at the lower end of the spectrum, e.g. B. 20 to 30 Hz, the sampling interval can be 2 or even 4 msec (500 Hz or 250 Hz).

As known in seismics, for the first part of a seismic recording cycle, e.g. B. the first half a second to one second, high frequency signals received from shallow subterranean geological layers. Furthermore, these signals are picked up at sensor units that are closer to the launch site the reflected signals did not have time to reach the sensor units on more distant parts of the cable. Later in the recording cycle are the seismic signals coming from deeper geological layers are reflected, characterized by significantly lower signal frequencies.

At the beginning of a recording cycle, for example over the first second, it may be desirable to have the query seismic data with a sampling interval of 0.5 msec.

95 96

units and associated seismic sensors are used which are close to the central station 2, e.g. B. the units 11 Ia. 11 id. Accordingly, an S 1 pulse and a DATA control pulse are transmitted from the central station 2. The width of the DATA pulse c for the four units is 111 a, 111 d

(4 - 1) 600 + 300 »2100nsec.

The initial delay of the OATE / V pulse is zero because there are no units between the central station 2 and the first transmitter / receiver unit 11 1a.

At the end of the 2000th scan (1 see) and for the remainder of the recording cycle, the seismic data from the seismic sensor units 21 at the input channels in FIG. 43 with intervals lower frequency can be queried, e.g. B. sampling intervals of 2 msec, and all transceiver units are activated. Thus, for the 2001 a new control pulse with a larger width is transmitted simultaneously with the 51 pulse. The width of this new control impulse is

(7 - 1) 600 + 300 - 3900nsec,

to make the seven transceiver units 111 «, HIg effective. The initial delay is zero as above. If, on the other hand, all transmitter-receiver units are to become effective, the DATA moo- ting can be "ON" , ie have an "infinite" length, during the entire recording cycle.

For this purpose 28 sheets of drawings

40

Claims (30)

Patent address: 1. Seismische Datenververarbeitungeinrichtu.ng with a central station and a seismic cable arrangement connected to it, over the seismic data recorded and in multiplex technology can be transmitted to the central station, the cable arrangement being divided into a plurality of cable sections arranged one behind the other. each comprising at least one group of spaced apart elementary sensor units and a connector module having a contains electronic transmitter and receiver circuit for time-divided interrogation of the associated sensor units, characterized in that - each connector module to a broadband Transmission connection is connected and a first multiplex slufe (122, F i g. 5) for selective successive interrogation of the Analog output of each elementary sensor unit (21, Fig. 1) of the assigned group and a converter circuit (114, 124, 126, 128; Fig. 5) via which the signals from each sensor unit on the cable transmission path are switchable, and that The outputs of at least one of the converter circuits through a second multiplex stage are sequentially transferable to the central station (2). 2. Device according to claim 1, characterized in that - the transmission connection a data channel (4090, Fig. 43), a first control channel (4091, Fig. 43) and a second control channel (4092. F i g. 43) includes, - the signal transit time in the two control channels is different, and that - responsive in each transmitter and receiver circuit (111, Fig.47) each have a control network (132, Fig. 5) is present, the ^r to the simultaneous Eintref- 4> fen received via the two control signal channels control signals, and depending on the response triggers a control command (Figs. 5 and 43). 50 3. Device according to claim 2, characterized by a delay line (4132, Fig.46) in the central station (2) for the delayed transmission of control signals via the control channels (4091, 46) to the transmitter-receiver circuits at different times in such a way that the control signals arrive simultaneously in a respectively selected transmitter-receiver circuit (FIG. 46). 4. Device according to claim 3, characterized by a pulse width setting circuit (4130, t> o F i g. 47) in the central station (2) to change the pulse widths of one of the two control signals so that these control signals in more than one of the selected transceiver circuits coincide (Fig. 47). μ 5. Device according to claim 4, characterized in that a control circuit (4018. F- "i g. 4t>) in the central station for changing the other of the two control signals is available (Fig. 46, 47). 6. Device according to claim 3, characterized by a plurality of delay lines (4132) arranged in one of the control channels (4091) for delaying the delivery of the control signal via said control channel (FIG. 46). 7. Device according to claim 6, characterized in that the delay lines (4132, F i g. 46) are all set to the same delay time. 8. Device according to claims 5 and / or 6, characterized in that each of the transmitter-receiver circuits has a test circuit (4143) which is responsive to the simultaneous occurrence of one Control signal at the input and output of the delay line responds (F i g. 46 and 48). 9. Device according to claim 7, characterized in that the transmission time for the control signals corresponds to an integral multiple the delay time caused by the delay line (4132, FIG. 46) can be set. IC. Device according to claims 4 and / or 7, characterized in that the pulse width setting circuit (4130, Fig. 47) is used to change the Transmission duration of the control signals transmitted via the first control channel (409t, FIG. 47) and that this control channel has a signal delay time greater than an integral multiple of the control signal delay time (FIG. 47). 11. Device according to claim 6, characterized in that the first control channel (4091, Fig. 48) is an interrogation or sampling channel to which a majority selection sound (4114, FIG. 48) is connected in each transmitter-receiver circuit, which responds to control signals arriving simultaneously via the two control channels and disconnects the relevant Scndcr-Receiver circuit from the data channel when the control signals are sent to the relevant Transmitter-receiver circuit arrive at the same time (Fig. 48). 12. Device according to claim 5, characterized in that that - The control circuit (4018), a circuit group for switching a first control signal to the first control channel (4091, FIG. 46) and a delay line, via which a second control signal having a certain first signal characteristic to the second control channel (4090) is switchable, and that - a signal test device (4038, Fig. 45) for resetting the multiplex circuit (122) a selected one of said inputs is present when the first and second Control signal arrive at the same time in the relevant transmitter-receiver circuit (Figs. 43,44,45,46). 13. Device according to claim 12, characterized in that - By the control circuit (4018) control signals with a second signal characteristic to the other control channel (4090) are switchable, and that - the multiplex sound (122) to the control signal with the second signal characteristic speaks, (ig F. 43.44) by a different one of said inputs (21) to the output channel (4092 ') to switch. 14. Device according to claim 1, characterized by a control circuit contained in the central station (2) (4018. Fig. 46) for issuing and transmitting a sequence of control signals via the first control channel (4091. Fig.46) such that the multiplex circuit (122) in a subgroup of Transmitter-receiver circuits (111c to llle, FIG. 47) simultaneously each equally valued the Inputs of each subgroup to the assigned output channels in a predeterminable order switches on (Fig. 43, 44, 47). 15. Device according to claim 14, characterized in that that first of all all the first inputs of all transmitter-receiver circuits (111) of a certain Subgroups one after the other and then all the second inputs of the transmitter-receiver circuits the group concerned can be connected to the output channel (4092 ', Fig. 44) one after the other are. 16. Device according to claim 1, characterized in that that in every input for seismic signals there is a high-pass filter, the one connected in series Capacitor (123 ', Fig. 16) and a resistor (315 ", Fig. 16) common to the inputs and that the resistor is arranged in the output of the multiplex circuit (122) (Fig. 16). 17. Device according to claim 16, characterized by a cutoff frequency setting circuit (316, Fig. 16) for changing the frequency response of the High-pass filter by changing the time during which one of the named inputs to the multi-J5 plex circuit (122, Fig. 16) with the aforesaid Resistor (315 ") is connected. 18. Device according to claim 16, characterized in that the high-pass filter has a Grcn / frc- quenz 40 f ₀ = [\ I (2jtRCJI D / 7]
having, where - with R the ohmic resistance of the common resistor (315 "), - with C the capacitance of said capacitor (123 '), - with D the time during which one of the named inputs is connected to the common resistor, and - with T that time is designated that the multiplex circuit (122) is required to scan all inputs (Fig. 16). v, 19. Device according to claim 16, characterized in that that - One input of the multiplex circuit (122, Fig. 38) is connected to a grounded test channel (Co) w), - a series capacitor (1051) / between the common resistor (140) and the output channel (4092 ', Fig. 44) is arranged, and that μ - There is a switch circuit (3026, Fig. 38) for applying a bias signal to the series capacitor which is approximately the same size but opposite in polarity to the undesired signal at the junction between the multiplex circuit and the series capacitor when the multiplex circuit has the Test channel (Co) switches to the output channel (Fig. 38,44). 20. Device according to one of claims 12 to 19, characterized by - An amplifier cascade circuit (124) comprising a plurality of amplifiers (A \ to A _n ), which is arranged between the multiplex circuit (122) and the output channel (4092 '), the gain of each amplifier being switchable between ONE and a higher value and the higher gain factors of the individual amplifiers are different, - An adjustable reference voltage source (3144) for supplying a reference voltage to each amplifier, which is inversely proportional to the gain of that particular amplifier Amplifier, A control network responsive to the second control signal with the second signal characteristic (132) to switch the amplification factors of the individual amplifiers, - a comparator circuit (3138) for comparing the absolute value of the output voltage of the amplifier cascade circuit with a signal, that of the first reference voltage of the amplifier with the greatest gain factor corresponds, with the control network setting the amplifier in question to a high gain factor switches when the specified output voltage is lower than the reference voltage, and - An additional circuit that connects to the comparator circuit and the control network cooperates to switch the gain the corresponding amplifier depending on the comparison of the output voltages the amplifier cascade circuit with the individual reference voltages of the relevant Amplifier (Figs. 39 and 44). 21. Device according to claim 20, characterized in that the largest gain factor of a selected amplifier is equal to C, - = 2 ^ ->> , where C is the largest gain factor of the amplifier / th amplifier of the amplifier cascade circuit when the amplifier is ordered with decreasing gain factor and the number of amplifiers is m . 22. Device according to claim 20, characterized in that - a capacitor (3138) is connected in series with the input of each amplifier, - A reset circuit (3174, 3176) is present in the control network (132), which switches the amplifier cascade circuit (124) to a test input (Co) of the multiplex circuit (122) that is not acted upon by seismic signals, in order to adjust all amplifiers of the amplifier cascade circuit to the gain Bring HINS / u , and that - The output signal of the amplifier can be switched to the capacitor via a feedback circuit (3184) to produce an output signal store of the same size and opposite polarity (F i g. 38,39,40). -> 23. Device according to claim 22, characterized in that - An analog / digital converter (126) is arranged between the amplifier cascade circuit (124) and an output signal register (128) which digitizes the amplified output signal and switches the digital signal to the data channel (4052 '), - A sensor group (21) is connected to each input (C \ to C) of the multiplex circuit (127). and that - in the central station (2) one of the seismic ones Signal processing device (4020) connected to the data channel which takes over the digital data supplied by the sensor groups and recorded as seismic signals (Figs. 43 and 44). 24. Device according to claim 23, characterized by - one in each transmitter-receiver circuit an- jo Ordered calibration circuit (136) for the definition of normalization coefficients in order to relative To compensate for differences in the signal output voltage of each sensor group, - A coefficient memory in the central station (2) (1055) for the programmed weighting of selected digital signals from the sensor groups and - Multipliers (1053a, 10536,) for multiplication of a respective weighted coefficient with a corresponding normalized coefficient and to supplement the product obtained with selected digital signals before they are in can be successively combined in a further processing stage (FIG. 5, 21). 25. Device according to claim 24, characterized in that - That the outputs of the sensor groups (21) are connected to the inputs (Q to C _n ) of the associated transmitter-receiver circuits (111), and that - A group shaping device (2124) is present in the signal processing device, which the seismic data selected before combining with other data with a Phase delay applied (Fig. 1. 34). 26. Device according to claim 2, characterized in that - A control circuit (4018) in the central station (2) to determine a first control signal Intervals on the first control channel switches to trigger a desired control sequence in a subset of the essentially b0 identical transmitter-receiver circuits (purple to IIIg; Fig. 47) which are arranged at regular intervals and which are connected to the central station (2) via the first and second control channel (4090, 4091) and the data channel, - A delay line (4102, FIG. 46) is assigned to the first control channel for the purpose of delay the signal run time of the first control signal in the first control channel by a specified one Amount in each transmitter-receiver circuit, - Delay circuits assigned to the second control channel in the central station (2) (4132) are present, via which the second control signal is compared to the first signal specified delay time can be switched to the second control channel, such that the delay time for the second signal a first integer multiple of said amount of the individual delay times of the first control signal, and that - in each transmitter-receiver circuit (111) Signal coincidence detector (4114) is present, which indicates the simultaneous occurrence of the two control signals checked (Fig. 46, 47, 48). 27. Device according to claim 26, characterized in that the delay circuits in the central station (2) is assigned a pulse width setting circuit (4130) through which the duration of the second control signal by a second integer multiple of the said amount Individual delay can be extended in such a way that by changing the delay of the second control signal a certain transmitter-receiver circuit can be controlled (FIG. 47). 28. Device according to claim 27, characterized in that - Each transmitter-receiver circuit (111) has a number of input channels (Q to C _n ) for analog signals, - Each transmitter-receiver circuit is assigned the same number of seismic sensor groups (21) is, and that - Each transmitter-receiver circuit to the output signal of the signal incidence detector (4114, Fig. 48) suitable electronic circuit groups (3011. 3033) contains for Filtering, sampling, amplification and conversion of the seismic analog signals into digital data, during digital data of another channel via the data channel to the central station (2) are transferable (Fig. 37). 29. Device according to claim 28, characterized in that the control circuit (4018) is so constructed is that the digital data received in the central station (2) is in columns following the sequence correspond to the relevant transmitter-receiver circuits, and can be stored in lines that the sampling order of the analog signals in the transmitter-receiver circuits (Fig. 47). 30. Device according to claim 28, characterized in that - the data channel (4092) has a triple ne broadband transmission path (Du D ₂ , Di; F i g. 5) includes, and dal '. - The central station (2) has an error interrogation and majority selection circuit (1028, Fig. 21), via which differential data from two of the three broadband links can be recorded, so that an interruption on one of the three broadband transmission links can be detected (Fig. 5, 21.4.}).