JPS60174971A - Method and device for transmitting signal in ultrasonic depth finder - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a signal transmission method between an ultrasonic sounding device installed at a measurement location and an evaluation location remote from the measurement location. The ultrasound pulses are transmitted in successive transmission cycles at a location, and the echo pulses received after reflection at the target are converted into electrical signals, which are transmitted via a connecting line to the evaluation location and where the ultrasonic The present invention relates to a method for evaluating said electrical signals in order to determine a target distance from the travel time of a sonic noculus, and a device for implementing this method.

Conventional technology The method mentioned at the beginning is a method that uses ultrasonic acoustic sounding to
Often used to measure filling status. For this purpose, an ultrasonic transducer is arranged above the maximum luminous state occurring in the container, which transmits an ultrasonic transmission pulse ξ which reaches the filling located in the container. The ultrasound echoes reflected at the filling, 6 ls, are received by the same or a second ultrasound transducer and converted into electrical reception signals. From the travel time of the ultrasonic pulse, it is possible to calculate the distance from the ultrasonic transducer to the filling surface, and thus the filling state in the container. The excitation of the ultrasonic transducer for transmitting the ultrasonic pulse is carried out by an electric high-frequency pulse ξ having an ultrasonic frequency. These excitations.

The lus can have any desired a-lus shape (envelope), for example keyed to a rectangular shape.The electrical reception signal emitted by the ultrasound transducer upon reception of the echo ξ lus is , is a high-frequency node ξ of the same frequency, but its curve shape is defined by the transfer function of the ultrasound transducer and the propagation medium of the ultrasound, and is different from the curve shape of the excitation node. The amplitude of the signal is significantly small compared to the amplitude of the excitation pulse ξ.

Particularly when using acoustic sounding devices to measure the filling state, it is often necessary to be able to use the measurement results at a location remote from the measurement location.

On the one hand, the measuring points are often difficult to access for handling purposes and there are often unfavorable conditions there.

On the other hand, it is desirable to collect the measurement results of a plurality of measurement points centrally.

It is known to arrange all the electronic equipment at an evaluation location separate from the measurement location, so that at the measurement location only the ultrasonic transducer is connected to the electronic equipment of the evaluation location via a connecting line. It is provided. The high-frequency excitation ξ pulse is then generated at the evaluation location and transmitted to the ultrasound transducer at the measurement location, and the high-frequency output signal of the ultrasound transducer is transmitted to the evaluation location. In this method, the high-frequency received signals are evaluated at an evaluation point, where these signals can be analyzed in the respective desired manner.

However, in order to transmit high-frequency signals in both directions, special shielded cables are required, since the electrical high-frequency noise generated by the ultrasound transducer based on the ultrasound echo pulses is relatively weak. , cable length is limited.

Furthermore, since noise may be superimposed on the transmission path, this type of device is prone to failures.

Finally, the evaluation device must be precisely matched to the ultrasonic transducer being used in each case, so that a unique evaluation device is required for each fixed point on each side and must be matched anew each time it is replaced. It is necessary.

In a known method according to the problem that the invention seeks to solve, the main part of the electronic device is arranged in the measuring unit υ1 in the immediate vicinity of the ultrasound transducer. The front-end electronics includes a transmission noise generator which generates an electrical high-frequency noise ξ for the excitation reservoir of the ultrasonic transducer. Furthermore, the front-end electronics includes a receiving and measuring circuit that amplifies the electrical received signal emitted by the ultrasound transducer and processes the transit time between transmission and reception. A complete evaluation of the received signal is therefore carried out in the front-end electronics. The receiving and measuring circuit generates an output signal that is dependent on the travel time, which signal can be transmitted to a remote monitoring station without problems, for example as a direct current varying between 4 mA and 20 mA. This method allows cables of any line length to be laid in a customary manner, so that the monitoring station can be located at any desired distance from the measuring point. Signal transmission is resistant to failure. However, in this method, the ξ
Much of the information contained in the Luss shape no longer exists at the observation post. Therefore, the filling status is indicated, but how is this instruction realized at the monitoring station?
A situation may arise in which it is impossible to check whether or not it is correct.

The object of the present invention is to enable interference-free signal transmission in an ultrasonic sounding device over ordinary cables of any length and to analyze the majority of the information from the received signal at an evaluation point remote from the measuring point. It is an object of the present invention to provide a method and a device which can perform the evaluation without having to specially adapt the evaluation device to the ultrasonic transducer used each time.

According to the invention, the object is to generate electrical envelope signals representing the envelope of the echonolus ξ at the measurement location and to transmit these envelope signals via a connecting line to the evaluation location. It is solved by

Furthermore, the invention provides at least one ultrasonic transducer that is arranged at the measuring location and that the output side is connected to this ultrasonic transducer. a transmission noise generator for generating electrical high-frequency transmission pulses and an amplifier, the input side of which is connected to the ultrasound transducer, and a control unit for controlling the time sequence, which is arranged at the measuring point; In a device with a frontelectronic device and an evaluation device arranged at the evaluation point, which is connected to the frontelectronic device via a connecting line, the frontelectronic device is connected downstream to the amplifier. The evaluation device comprises an envelope generating circuit which is shown in FIG.

Effect of the Invention The invention is based on the recognition that all the information necessary for the evaluation of the received signal is contained in its envelope, while no carrier frequency is required for this purpose. The envelope signal generated at the measurement location therefore contains all the required information. The transmission of the envelope signal from the measurement location to the evaluation location can be carried out problem-free and fault-proof via conventional cables of any length. This is because the envelope signal has a significantly lower frequency and a smaller bandwidth than the GLS modulated high frequency signal. The envelope signal can of course be processed at the evaluation location in order to obtain the required measured values in the respective desired manner, in particular, of course, for measuring the transit time of the ultrasonic pulse. Furthermore, the envelope signal can be analyzed in the evaluation field to obtain additional information such as: For example, statistical selection of clear coincidence of signals, detection of double reflections,
The transmission status in the vessel can be monitored for the purpose of eliminating undesired fixed targets (interfering reflections), detecting whether the signal level does not fall below predetermined limit values, monitoring the correct functioning of front-end electronics, ultrasonic transducers, etc. This is for analysis.

The processing of the envelope signal does not presuppose any special adaptation of the evaluation device to detector-specific data, such as the ultrasound frequency used, the impedance of the ultrasound transducer, etc. This makes it possible, in particular, to connect different ultrasound transducers to the same evaluation device without having to adjust their chambers. This makes it possible to combine a relatively large number of ultrasonic sounding devices into the same evaluation device, thereby making it possible to use, for example, the evaluation device required for measuring the filling state in a relatively large number of containers. can be significantly reduced.

According to an advantageous embodiment of the method according to the invention, the generation and transmission of the envelope signal takes place in the first time segment of each transmission period, the duration of the first time segment being at least the maximum time period during which the ultrasonic pulse occurs. equal to the travel time and generated at the measurement point in the second segment of each transmission period,
Electrical signals characterizing the parameters required for the evaluation of the envelope signal are transmitted to the evaluation location via the same connection.

By transmitting further low-frequency electrical signals via the same connection line, it is possible to reproduce the supplementary information at the evaluation point and to improve the measurement accuracy and fault safety. That is, for example, the temperature of the ultrasound propagation medium (i.e. the air above the filling in the container) is
This is important information for the accuracy of filling state measurement. This is because the propagation speed of ultrasound is temperature dependent and therefore temperature is involved in dividing the distance traveled from the measured travel time. One of the additionally transmitted signals is therefore advantageously characteristic of the temperature of the propagation medium. Safety against disturbances can be improved by bringing the envelope signal of the received signal, which is very weak and has very different levels depending on the measuring distance, to a sufficiently high level by adjusting the amplification in the front electronics. can be improved.

However, this eliminates the information contained in the echo amplitudes that accounts for the different transmission conditions. One of the additionally transmitted signals therefore preferably characterizes the amplitude of the received echo pulse. This signal can be derived, for example, from an amplification adjustment voltage.

Furthermore, by dividing each transmission period into two time segments, each time during the second time segment at least one control signal that is distinguishable from the low-frequency electrical signal transmitted in the same time segment is transmitted to the same This means that the envelope signal can be transmitted via the connecting line from the evaluation location to the measurement location without any interference. This makes it possible to control certain functions in the front-end electronic device from the evaluation point.

Embodiments Next, the present invention will be explained in detail with reference to the drawings, with reference to the illustrated embodiments.

FIG. 1 shows a container 10 arranged at a measuring point M. FIG.

A filling material 11 is contained in the container.

In order to measure the filling in the container 10, an ultrasonic transducer 12 is arranged on the upper side of the container above the maximum filling that occurs. The ultrasonic transducer periodically generates ultrasonic transmission pulses ξ directed downwardly toward the filling 11 in the container and receives ultrasonic echo pulses reflected from the surface of the filling 11. and converts it into an electrical reception signal. The travel time of the ultrasonic nosolus from the ultrasonic transducer 12 to the surface of the filling 11 and from there back to the ultrasonic transducer 12 is equal to the time it takes for the ultrasonic waves to travel within the container at the known propagation speed of the ultrasonic waves. and therefore also the filling condition in the container. The propagation speed of the ultrasound waves depends in particular on the temperature of the propagation medium, which in the illustrated example is air above the filling in the container. In order to be able to take account of the influence of temperature on the propagation velocity, a temperature detector 13 is provided within the vessel which delivers an electrical output signal that is dependent on the temperature within the vessel.

The ultrasonic transducer 12 and the temperature sensor 13 are connected to a front electronic device 14 which is likewise arranged in the immediate vicinity of the container 10 at the measuring point MK. 1 electric high frequency transmission to 14 ultrasonic transducers 12 in the front electronic device, 1 pulse transmission,
A converter converts these ξ scales into ultrasonic transmitters ξ. The electronic device receives ultrasonic echoes from the ultrasonic transducer 12/,
2. Receive an electrical reception signal corresponding to the signal. Furthermore, the front-end electronics@14 receives the output signal of the temperature sensor 13.

The preelectronic device 14 is connected via a connecting line 15 to an evaluation device 16 which is located at an evaluation point AK which is remote from the measuring point M. The evaluation device 16 has a first K signal processing circuit 17 .

A running time measuring device 18 is connected downstream to this circuit. The signal processing circuit is connected from the front-end electronics 14 to the connection line 15
The signals transmitted via the controller are processed in accordance with the evaluation to be carried out. The transit time measuring device 18 determines the transit time of the ultrasonic nosolus in the container 10 from the signal processed by the signal processing circuit 17, and the measuring device indicates on the output side the filling state in the container 10. FIG. 2 shows a block circuit diagram of the electronic circuitry included in the front-end electronics 14.

FIG. 2 shows the connections of the ultrasonic transducer 12 and the temperature detector 13 as well as this front electronic device 14 to the entire evaluation device 16!
15 is also shown.

The front-end electronics 14 has a control unit 20 which controls the time course of all processes in the front-end electronics. In particular, the control unit 20 sends periodic trigonometric pulses to a transmission pulse generator 21 at an output 20a. The output side of this noise generator is connected to an ultrasonic transducer 12. The transmission noise generators 21 each send out a high frequency transmission noise ξ based on a trigger pulse of tl.

This e-lus has the desired optimal ultrasound frequency and can be converted by the ultrasound transducer 12 into an ultrasonic transmission, o-rus. The duration of each transmit pulse is shorter than the transmit period. The transmission period is longer than the maximum transit time during which the ultrasonic pulse ξ occurs in the container 10, i.e. when the container is empty or in the minimum filling state that occurs, as will be explained in more detail later with reference to FIG. Thus, in the illustrated embodiment, the maximum travel time of the ultrasonic pulse from the ultrasonic transducer 12 to the surface of the filling 17 in the container 10 and back to the ultrasonic transducer 12 is 250 m5.
The transmission period for one sword is 500 ms, Tpk, and the duration of each bonito transmission pulse is Ts.
Assume that the distance is 1m5f and G. Therefore the control unit 20
is sent in each case at periodic time intervals of 50 ms to a pulse generator 21, which transmits a high-frequency transmission of a duration of 1 ms to the ultrasonic transducer I2, o Apply russ.

The birds periodically delivered at the output 20a of the control unit 20 can also be supplied to a blocking time interval circuit 22. The 1m1 stop time interval circuit 22, formed in the simplest case by a monostable multivibrator, sends out a blocking signal from its output on the basis of the respective trigger signal. The duration TBL of this blocking signal is the "blocking time interval",
That is, it corresponds to the time during which the ultrasound transducer 12 is unable to receive valid echo pulses. This is, on the one hand, the time during which the transmit pulse is emitted and, on the other hand, the oscillation decay time following each transmit nodal pulse, ie the time during which the ultrasonic transducer oscillates at a reduced amplitude. A similar electrical signal is generated at the connection terminal of the ultrasonic transducer 12 due to the reduced amplitude vibration, and the amplitude of the electrical reception signal derived from the echo pulse that arrives during the vibration period is gradually attenuated. When the amplitude of the signal is smaller, it cannot be evaluated. The blocking time interval depends on the characteristics of the ultrasound transducer, the ambient conditions (temperature)
They can also vary widely depending on the installation conditions. The duration of the blocking signal emitted by the blocking time interval circuit 22 can therefore be set in such a way that it exceeds the maximum vibration damping time that occurs by a temporally safe factor.

The ultrasound transducer 12 is connected to the input 24a of an amplifier 24, which amplifies the electrical reception signal that the ultrasound transducer 12 sends out each time it receives an ultrasound echo pulse. amplifier 24
The amplification degree of can be controlled by the voltage applied to the amplification control input terminal 24b. Furthermore, the amplifier 24 has a blocking input 24c connected to the output of the blocking time interval circuit 22.
f, so that the amplifier is blocked for the duration of each blocking signal that is not sent out by the blocking time interval circuit 221. Therefore, the vibrations of the amplifier 24 generated by the high-frequency transmission noise ξ sent out from the transmission noise generator 21 as well as the vibration damping of the ultrasonic transducer 12 are transmitted without any force and there is a blocking time on the output side of the amplifier 24. Only echo signals arriving after the elapse of the interval appear.

In each transmission cycle during filling state measurement,
Only valid received signals result from ultrasound echo pulses reflected at the surface of the filling 11. This reception signal is a high-frequency signal having the same carrier frequency as the high-frequency transmission pulse sent out from the transmission pulse generator 21, and its curve shape is determined by the transmission characteristics of the ultrasonic transducer 12 and the transmission state in the container 10. Since it is defined by
This is different from the distorted shape of the transmission noll ξ. Diagram A in FIG. 3 shows the high-frequency transmission noise ξ which can be sent out from the transmission noise ξ pulse generator 21 as flll, assuming that the transmission noise ξ is keyed into a rectangular shape.

Diagram B of FIG. 3 shows the received signal at the output of the amplifier 24, which corresponds to the received ultrasound echo nolus ξ. The time interval TM between the transmitting ξrus and the receiving ξrus corresponds to the transit time of the ultrasound in the container 10,
In turn, it represents the filling state. The amplitude and time course of the echo signal fully reproduce the transmission state in the container.On the output side of the amplifier 24, an envelope generating circuit 2 generates an output signal corresponding to the time course of the envelope of the output signal of the amplifier 24.
5 is connected.

Diagram C in FIG. 3 shows the envelope signal extracted at the output of the envelope generating circuit 25 for the received signal of diagram B. This envelope signal is a snow pressure, or pulse, which has a time course corresponding to the envelope of the high-frequency signal of diagram B. This voltage norm ξ therefore contains all the information necessary for the evaluation and determination of the transmission state. The envelope generating circuit 25 can be formed in the simplest case by an amplitude modulator, optionally upstream with a bandpass filter tuned to the carrier frequency of the received signal.

The output side of the envelope generating circuit 25 is connected to the signal input fArJ 26 a of the logic switch circuit 26.

A connecting line 15 is connected to the output side of this circuit. This logic switch circuit 26 has a control input 27ai, which is connected to a second output 20b of the control unit 20. A further control input of the logic switch circuit 2G receives the blocking signal from the output of the blocking time interval circuit 22.

Furthermore, the output signal of the envelope generation circuit 25 is sent to an amplification degree adjuster 28.
is supplied to the input side of the This amplification adjuster is the amplifier 24
The amplitude of the envelope signal corresponding to the received signal is predetermined 117j and sent to the amplification control manual side 24b to maintain it at a constant value. In this way, significant fluctuations in the echo amplitude, which are caused by different measuring distances on the one hand and different propagation conditions for the ultrasound waves on the other hand, are compensated for. In this connection, in filling state measurements as well as in most other applications of sounding devices, in each transmission period an effective echo signal corresponding to a given target distance is obtained which generally varies only slowly and continuously. The fact that there is no is important. Therefore, it is easy to adjust the amplitude of these effective echo nodules to keep them constant. If appropriate, additional measures can be taken to suppress disturbance noises or multiple echoes.

However, due to the amplification adjustment, the information contained in the amplitude of the echo signal is lost through echo attenuation during the process from the ultrasonic transducer to the filling surface and back to the ultrasonic transducer. . Since these information may also be important for the evaluation of the echo signal in the evaluation device, no separate information regarding the echo amplitude is additionally transmitted to the evaluation device. For this purpose, an amplification adjustment voltage delivered by the amplification regulator 28 can be applied to the input 29a of the voltage/time converter 29. The output of this converter is connected to a further control input 27c of the logic switch circuit 26.

A further input 29b of the voltage/time converter 29 is connected to an output 20b of the control unit 20. The voltage/time converter 29 sends out the entire output signal in each case according to the signal supplied to the input 29b. The duration of this output signal TV
is dependent on the amplification adjustment voltage applied to the input 29a.Finally, the output signal of the temperature sensor 13 is applied to a further signal input 26b of the post-amplification wheel switching circuit 26 in the amplifier 3°.

The logic switch circuit 26 is an electronic switching circuit which connects the connecting line 15 sequentially to different signal sources under the control of time control signals supplied by the control unit) 20° blocking time interval circuit 22 and the voltage/time converter 29. It is a device.

In the diagram of FIG. 4, the duration of the signal of duration T, -500, is not drawn to scale for clarity.

According to the numerical example given above, the duration of the transmission period TPO is selected to be at least twice the longest running time during which the echonolus ξ occurs. The transmission period is divided into two equally large time periods T and TP2 with a duration of 250 m5. Section 1 Time TP1 is used for the transmission of the envelope signal corresponding to the echonolus ξ, and the remaining signal required for the evaluation of the envelope signal in the evaluation device 16 is transmitted in -auspicious time TP2. be done. Of course, there are two time periods TP.
It is not necessary that 1 and TP2 be the same size. For example, for the transmission of the remaining signals. The segment time TP2 provided for this purpose can also be made smaller than the segment time TP1 used for receiving and transmitting the echo signal.

At the time LO at the beginning of each transmission period, the control unit 20 is sent out from the output 20a!・A signal gold is applied to the control input terminal 27 of the logic switch circuit 26 in synchronization with the signal ξ. This signal activates the logic switch circuit 26 at a constant DC voltage of 1 J, preferably at the supply voltage V
. 0 is applied to line 151. The beginning of this voltage step signals the evaluation device 16 when to send out the ultrasonic transmission pulse ξ and thus the beginning of the measuring time. DC voltage potential V. 0
The duration of the transmission of is preferably equal to the duration of the transmitted pulse T8
In the numerical example given here, it is 1 ms. This duration is exaggerated in FIG. 4 compared to the duration T1° of the transmission cycle.

After the transmission time T8 has elapsed, the logic switch circuit 26 is at the time t,
Under the action of the blocking signal applied from the blocking time interval circuit 22 to the control input 27b, the DC voltage applied to the connecting line 15 at a relatively low value U1., for example 2/3 voo. Move to a position where it can be lowered. This state is l
! II is maintained for the duration of the stop time T13L determined by the open time interval circuit 22. This blocking time is 6 ms at the beginning of the transmission noise ξ in the numerical example given above. This indicates to the evaluation device 16 the duration of the blocking time. The blocking time T131 is also shown in an exaggerated manner in FIG.

After the termination of the blocking time TBL at time t2, the logic switch circuit 26 connects the connection line 15 to the signal input terminal 26a.

Therefore, the first segment time T1 of the transmission period coincides with the blocking time.
In the remaining part, an envelope signal UII corresponding to the echonolus ξ is transmitted to the evaluation device 16. The evaluation device 16 determines the transmission time t. Detect the time interval TM'ff between the leading edge of the envelope signal UI+ and the point in time when the leading edge of the envelope signal UI+ reaches a predetermined threshold value, and from there detect the time interval TM'ff that is transmitted using the remaining signal. The full filling state in the container IO is calculated taking into consideration.

2. After 50+++s, the control unit 20 returns to time t3.
In addition, the control input side 27 of the logic switch circuit 26 is newly added.
a, the supply voltage V. A synchronization norm ξ with a value of 0 and a duration of l ms. Add a signal that causes the entire signal to be sent out. This synchronization nolus ξ U. instructs the evaluation device 16 to start the first segment time T12 of the transmission cycle.

However, in the same period, orus U. Since a trigger pulse ξ does not occur at the output 20a of the control unit 20, no ultrasonic transmission pulse ξ is transmitted at this point, and the blocking time interval circuit 22 is connected to the control input 27b.
Do not apply a blocking signal to the The voltage level on the connecting line 15 is therefore synchronized at one time t4, or the voltage level U. At the end of , it drops to 0■. In this case, since no voltage step occurs to 2/3 voo, the evaluation unit 16
It can be distinguished into two partitioned times, Tp, and T,2.

It is applied to the control input side 27c. Voltage/time jar 181
On Koyama too! After the elapse of time TV, the logic switch circuit 26 switches to time t5.
connection kf' between the signal input end 26b and the connection line 15
, so that the output voltage of amplifier 30 is transmitted to connection line 15 . Therefore, the connecting line 15 is detected by the temperature detector 13 during the remainder of the segment time "P2".
A voltage UT representing the temperature inside the container is introduced. This voltage is set to a new voltage value V at the beginning of the next transmission cycle. , : Do you have the same synchronization? The point at which the signal can be transmitted via the connection line 15 to
’ is maintained until ’.

Duration TV determined by voltage/time converter 29
depends on the amplification adjustment voltage at the output of the amplification regulator 28 and is therefore a measure for the echo amplitude. The voltage step change time t5 between the value OV and the temperature voltage U,1 is therefore shifted depending on the echo amplitude. That is, in the divided time TP2, echo amplitude information is transmitted by a time signal, and temperature information is transmitted by a voltage level.

In this way, all the information required at the evaluation point is transmitted via the connection line 15 by means of very low-frequency signals. The connecting line 15 can therefore be a simple, unscreened conductor, and the transmitted signal is not significantly attenuated even if the length of the connecting line is very long.

Of course, it is also possible to transmit different information signals in a different temporal order over the connection line, or the transmission format can be varied arbitrarily, in which case, for example, the echo amplitude is expressed by a voltage value and the temperature is represented by time information. Furthermore, further information of interest can be transmitted to the evaluation device at segment time TP2 using a similar low-frequency signal.

Of course, the signal processing circuit 17 included in the evaluation device 16
This configuration, as well as the configuration of the transit time measuring device 18, which is adapted to be suitable for processing the transmitted envelope signal and the transmitted residual signal, can be determined by a person skilled in the art with knowledge of the transmitted signals. can be deduced without any difficulty, so a detailed explanation is unnecessary. For example, the signal processing circuit 17
A suitably programmed microcomputer can also be used as an essential component of the running time measuring device 18. The transmitted signals are then digitized at the evaluation station, stored and processed by the microphone 11 computer.

A modified embodiment of the filling measuring device will be explained based on FIGS. 5 to 7. In this embodiment, the amplification dust of the amplifier 24 is measured at the second
The evaluation device 16 is passed through the same tangent line 15 during the segmented time.
It is controlled by a signal that can be transmitted in the opposite direction from to the front-end electronics 14.

Figure 5 shows the front electronic device 1 located at the measurement point M on the left side.
4 is illustrated, and on the right side is a block circuit diagram of the evaluation device 16 provided at evaluation point A. In between, the block circuit diagram of the evaluation device 16 provided at evaluation point A is shown, and between them, the length can be set to any desired length, so the broken line The block circuit diagram of the front-end electronics 14, in which the connecting lines 15 are illustrated, corresponds approximately to that shown in FIGS. Different circuit components are numbered the same as in FIG. 2 and will not be described again. The front electronics 14 of FIG. 5 differs from that of FIG. 2 only in the following respects: On the output side of the logic switch circuit 26, all signal voltage connections are supplied in each case from the logic switch circuit 26. 15. A current driver 40 for converting the current into a current that is transmitted to the evaluation device 16 is connected downstream. That is, the connecting line 15 is now driven not as a voltage transmission line but as a current loop.

The diagram in FIG. 7 shows the time course of the current ■ transmitted via the connecting line 15. The diagram in FIG. This course corresponds to the time course of the voltage diagram in FIG. In this case, the voltage values UA, UB, UH shown in Fig. 2.

Uo and U,1. is the current value ■A, “B”, “H”
The maximum current value corresponding to the positive supply voltage V.0 is, for example, 10 mA.

A detector circuit 50 is connected to the current liners 40, which has a control input connected to a further output 20c of the control unit 20.

Amplification adjuster 2 provided in the adjustment loop in Fig. 2
8 is replaced by an amplification control circuit 60 whose input side is connected to the output side of the detector circuit 50. The output side of the amplification control circuit 60 is the amplification adjuster 28 shown in FIG.
Similarly to the output side of the amplifier 24, the amplification control input terminal 24b
and electric power (E/time converter 29 human power 11j! I 29
Connected to 2.

The evaluation device 16 has a microphone computer 70 which is programmed to carry out the functions of the signal processing circuit 17 and the running time measurement device 18 of FIG. A resistor 71 connected between the two terminals closes the current loop.The voltage drop across this resistor 71 is applied to the input terminal of an AD converter 72, and its digital output signal is supplied to the microcomputer 70. .

The output side of the microcomputer 70 controls a switch 73 by which a voltage of -1 to 24 cm can be applied to the connecting line 15.

This voltage is the positive supply voltage V used in front-end electronics, for example +12V. . , 1: extremely high.

By closing the switch 73, a +24V voltage pulse of 1J is generated.
In the second segment of the transmission period for the transmission of 8, a time window TP is provided, which is set such that the end point 2 of the variable duration TV cannot in any case occur within the time window. . In Figure 7, the maximum period of audience is 140m5. It is assumed that l:v is small. The time window TF is synchronized)ξrus■. The end of flk starts at time t6 of 140 ms or 96
has a duration of 0 ms, resulting in a synchronization noise ξ. The time point t has a time interval of 200 ms from the end of
It ends at 7.

The presence or absence of the voltage pulse US during the time window T period is determined by the evaluation device 1.
The control information transmitted from 6 to the front-end electronics is shown. Closing the switch 73 causes the connection line 15 to receive voltage/Grus U8.
When the voltage is applied completely, it means "increase the amplification degree". If the voltage/ξ pulse U8 does not occur during the time window TF, it means "reduce the amplification degree". A detector circuit 50 in the front-end electronics 14 detects the presence or absence of a voltage norm U8 in each time window T2 and causes an amplification control circuit 60 to vary the amplification of the amplifier 24 accordingly.

An embodiment of the current P rhino 40, detector circuit 5o and amplification control circuit 60 is illustrated in relative detail in FIG.

The current P rhino 40 has an amplifier 41 that acts as a voltage/current converter. A connection III 15 is connected to the output of the amplifier via a resistor 42. Since the current I transmitted from the amplifier 41 via the connecting line 15 is always positive (FIG. 7), this current is always connected to the terminal of the resistor 42 connected to the output side of the amplifier 41 at the resistor 42. A voltage drop is generated to lead to a relatively high potential.

The amplifier 41 is configured to be saturated at a positive supply voltage voo of +12v. Therefore, the evaluation device [
16, when a voltage higher than +12V is applied to the connecting wire 1'5K by closing the switch 73, the amplifier 41
is no longer able to deliver current and the polarity at resistor 42 is reversed. This polarity reversal is caused by the detector circuit 50
detected by.

The detector circuit 50 includes a comparator 51 formed by an operational amplifier with a differential input fJIU. The inverting input of the operational amplifier is connected to the tap of a voltage divider formed by two resistors 52, 53). This voltage divider is connected between a terminal of a resistor 42, which is connected to an amplifier 41, and a terminal. The non-inverting input side of the operational amplifier is connected to two resistors 54, 55, which are connected to the connecting line 15, between the terminals of the resistor 42 and ground.
It is connected to the tap of the voltage divider formed from the cap. When the potential applied to the inverting input side is higher than the potential applied to the non-inverting input side, the output side of the operational amplifier receives a negative voltage, rf
, leading to.

That is, when the potential state is reversed, the output voltage of the operational amplifier becomes positive.

The output signal of the comparator 51 is the gate circuit 56? via the holding element 57. The gating circuit 56 is controlled by a time-controlled circuit formed from two monostable multinomial ibrators 58 and 59 connected in cascade. The two monostable multivibrators 58 and 59 can be triggered by negative-going pulse edges.

The retention time of the monostable multinomial ibrator 58 is 140
ms, and the time keeping time of the monostable multivibrator 59 is 6'Oms.

The trigger input terminal of the monostable multinomial ibrator 58 is connected to the output side 20CK of the control unit 20. The control unit 20 outputs (120, synchronized at each transmission cycle) ξrus I. coincides temporally with (Fig. 7) ξ
Send out Luz. A monostable multi-nogle ζibrator 58 is triggered by the trailing edge of this noggle. 140ms
After the retention time of 58
triggers the monostable multinomial ibrator 59. The output side of the monostable multinomial ibrator 59 is connected to the gate circuit 5.
6, so that the gate circuit 56 is open for the duration of the holding time of the monostable multinomial ibrator 59. As can be clearly seen from FIG.
, corresponds to . Therefore, in each transmission period, the time window TF
The output voltage of the comparator 51 that occurs during the period of
The transmission can be completed. This voltage is stored in the holding element until the beginning of the time window in the next transmission period.

Amplification control circuit 60 includes an integrator 61 formed by an operational amplifier 62 in a conventional manner. A capacitor 63 is provided in a feedback circuit extending from the output side of this amplifier to the inverting input side. The inverting input is connected via a resistor 64 to the output of the holding element 57 of the detector circuit 50, while the non-inverting input is connected to a fixed potential, for example ground potential. Corresponding to the known operation of this type of integrator, the output voltage of the operational amplifier 62 increases linearly when a constant negative voltage is applied to the input, and when a constant positive voltage is applied to the input. When joining, it descends linearly. An inverting amplifier 65 is connected downstream of the integrator 61. The output of this amplifier delivers an amplification control voltage to an amplifier 24 and a voltage/time converter 29.

As is clear from the foregoing description, the amplification of the amplifier 24 is increased continuously during and after each time window in which the voltage norm ξ U8 is applied to the connection line 15, while the voltage norm ξ It is continuously reduced during and after the time window in which U8 is not occurring. Thereby, the amplification dust of the amplifier 24 can be controlled by the evaluation device 16.

Instead of the amplification of the amplifier 24, it is also possible to control other functions of the front-end electronics by means of the voltage ξ pulse U8. In a corresponding manner, one detector circuit is provided for each time window in the entire design and in the front electronics for a plurality of temporally successive time windows in each transmission period, and these are connected to the seven associated time windows. It can also be controlled by a plurality of functional evaluation devices of the front electronics in such a way that it is detected whether a voltage or pulse has occurred. In each case, by applying significantly higher voltages to the connecting lines, it is ensured that the control signals transmitted from the monovalent device to the front-end electronics are clearly distinguishable from the envelope and information signals transmitted in the opposite direction. ing. By transmitting the control signal in the second time segment of each transmission cycle, it is ensured that the transmission of the envelope signal during the first time segment of the transmission cycle is not disturbed.

Effects of the Invention According to the invention, the entire envelope signal containing all the information generated at the measuring point is used, so that it can be transmitted over any length of ordinary unscreened cable.
Moreover, it is advantageous because it can be analyzed to obtain additional information. Furthermore, the device according to the invention has the advantage that no special alignment of the evaluation device 9 is required.

[Brief explanation of the drawing]

FIG. 1 is a block diagram illustrating the entire principle of a device configured according to the present invention for measuring the filling state in a container using an ultrasonic sounding device, and FIG. 3 is a waveform diagram showing the time course of the various signals occurring in the circuit of FIG. 2, and FIG. 4 is a block circuit diagram of the front-end electronics of the device; FIG. FIG. 5 is a signal waveform diagram sequentially showing transmitted signals in time, FIG.
7 is a circuit diagram showing in detail the configuration of some components of the front electronic device of FIG. 5, and FIG. FIG. 3 is a signal waveform diagram showing the passage of time of a signal. M...Measurement point, A...Evaluation point, 12...Ultrasound-
Wave converter, 13...Temperature detector, 14... Front electronic device, 15... Connection line, 16... Evaluation device, 17.
...Signal processing circuit, 18...Traveling patent application measuring device, 20
... Control unit, 21 ... Transmission pulse generator, 2
2... Blocking time interval circuit, 24.30... Amplifier. 25... Envelope generation circuit, 26... Logic switch circuit, 28... Amplification regulator, 29... Voltage/time converter, 43... Current driver, 50... Detector circuit . 60... Amplification control circuit, 73... Switch, TP
...Transmission cycle, "'P1,"P2...Division time h
UH' IH...Envelope signal, 1 no. ,■o...
Synchronization noise ξ, U8...control signal, TF...time window. Procedural amendment (formality) March 26, 1985 Commissioner of the Patent Office 1. Indication of case Patent Application No. 231447 of 1988 2
, Title of the invention: Signal transmission method and device in ultrasonic sounding device 3, Relationship with the case of the person making the amendment Name of patent applicant: Endres/Hauser Gesernjaft Mituto Be/Ulenkter Hafnong Land.
Konnoguni 4, Agent 5 Date of amendment order: February 26, 1985 (Date of dispatch) (1), (2), and (3) are all as attached.However, (3) is an engraving of the drawings (changed in content) None) Continued from page 1 0 Inventor Wolfram Berga 23438045.0 Vail Am Φ Rhein Badels Gerten
5 Steinen-Gerhard-Hauptmann-Strasse, Federal Republic of Germany 5-1

Claims (1)

[Claims] 1. A signal transmission method between an ultrasonic sounding device disposed at a measurement location and an evaluation location distant from the measurement location, the method comprising: It transmits an acoustic wave A pulse and converts the echo wave received after reflection at the target into an electrical signal, transmits the electrical signal via a connecting line to the evaluation point and there converts it from the path of the ultrasonic pulse ξ. In the method for evaluating said electrical signals in order to determine the target distance, an electrical envelope signal (UH: 111) is generated at the measuring point (M) representing the envelope of the echo and the oscillation. A signal transmission method in an ultrasonic sounding device, characterized in that the envelope signal (UH; IH) is transmitted to the evaluation point (A) via the connection line (15). 2. The generation and transmission of the envelope signal (U,: IHI,
The first of each transmission period (Tp) with a duration equal to the maximum transit time during which the ξ ruses (at least ultrasound) occur
The envelope signal ('TP 1 ) and generated at the measuring point CM) at the second segment time (T1)2) of the respective transmission period (TP).
The low frequency electrical signal characterizing the parameter ξ which is necessary for the evaluation of UH: IH) is connected to the same connection line (15).
Claim No. (8) to be transmitted to the evaluation point (8) via
A signal transmission method in the ultrasonic sounding device described in 2. 3. At the beginning of each segment time of the transmission period (TpJ) an electrical signal (UA, Uc; IA,
3. A signal transmission method in an ultrasonic acoustic sounding device according to claim 2, wherein the signal transmission method (IC) is transmitted to the evaluation point (A) via the same connection line. 4. The second segment time (T) of each transmission period (TP)
In P2), the electric signal (UT-: 1・p) characterizing the temperature of the propagation medium of the ultrasonic pulse ξ is evaluated at the evaluation point (
A) A method for transmitting a signal in an ultrasonic sounding device according to claim 2 or 3. 5 Each transmission period ('r1's second division time (T
F2) In the ultrasonic sounding device according to any one of claims 2 to 4, which transmits an electric signal characterizing the amplitude of the echo pulse received at (A) to the evaluation point (A). Signal transmission method. 6. An amplification adjustment circuit (24, 25, 28) that adjusts the envelope signal of the electric signal characterizing the amplitude of the received echo nolus to a constant level, which is included in the reception circuit.
A signal transmission method in an ultrasonic acoustic sounding device according to claim 5, wherein the signal is derived from the amplification adjustment voltage. 7. Each transmission period (Tp+ second segment time (
TF2) Claims 2 to 6 in which at least one of the electrical signals transmitted throughout the room is represented by amplitude information
A signal transmission method in an ultrasonic acoustic sounding device according to any one of the preceding paragraphs. 8. A signal transmission method in an ultrasonic sounding device according to claim 7, wherein the amplitude information is represented by a direct current voltage (UT). 9. A signal transmission method in an ultrasonic sounding device according to claim 7, in which the amplitude information is expressed by a direct current (ITI). 10. Each transmission period (second segment time t of TP +
Signal transmission in the ultrasonic sounding device according to any one of claims 2 to 9, wherein at least one of the signals transmitted during 't'p2) is represented by time information (Tv). Method. 11. A signal transmission method in an ultrasonic sounding device according to claim 10, wherein the time information (1'V) is expressed by the time point of switching from a certain field of view value to another field of view value. 12 Second division time (T, ) of each transmission period (T, )
In p2J, at least one control signal (tJs) distinguishable from the low-frequency electrical signal transmitted in the same segment time (TF2) is transferred from the evaluation point (Al to the measurement point (M) via the same connection line (15). ) A signal transmission method in an ultrasonic sounding device according to any one of claims 2 to 10. A voltage higher than any voltage is applied to the transmission line (15) during the signal transmission period during a predetermined time window (TF).
A method of transmitting a signal in an ultrasonic sounding device in which a signal is applied to connection i (+5) during a period of . 14 On the side where the ultrasonic sounding device is installed, the ultrasonic noise ξ is transmitted in consecutive transmission cycles at a fixed location, and the echo noise ξ received after reflection at the target is converted into an electrical signal, and the The electrical signal is transmitted via a connecting line to an evaluation point remote from the measuring point and there the ultrasonic wave ξ
an apparatus for carrying out the method for evaluating the electrical signals in order to determine the target distance from the travel time of the vehicle, the apparatus comprising: at least one ultrasonic transducer arranged at a measuring point;
It has an output side connected to the ultrasound transducer. a pre-electronic device comprising a transmitting pulse generator for generating an electrical high-frequency transmitting noise ξ and an amplifier whose input side is connected to the ultrasound transducer and a control unit for controlling the time sequence; and an evaluation device arranged at the evaluation point, which is connected via a connection line, the front electronic device (14) being connected to the envelope circuit downstream of the amplifier. The generation circuit (25) and the envelope generation circuit (
25) to the connection line (15), and the evaluation device (16) includes a signal processing circuit (17) for processing the envelope signal. A signal transmission device in an ultrasonic sounding device characterized by: 15. Connect the output side of the envelope generation circuit (25) to the connection line (15
) is controlled by the control unit (20) to transmit the first
At the segment time (TPl), the connection line is connected to the envelope generation circuit (
25), and each transmission period (T
15. A signal transmission device in an ultrasonic sounding device according to claim 14, which is controlled to connect to at least one other signal source in the second segment time ('l'p21) of P). 16. Claim 1, wherein one of the further signal sources is a temperature detector (13) for measuring the temperature of the ultrasound propagation medium.
A signal transmission device in the ultrasonic acoustic sounding device according to item 5. 17 Amplifier (2) included in front electronics (14)
4) is variable by the amplification control voltage, and one of the further signal sources supplies the logic switch circuit (26) with a signal dependent on the amplification control voltage. 17. A signal transmission device in an ultrasonic acoustic sounding device according to item 1 or 16. 18. Ultrasonic acoustics according to claim 17, characterized in that a voltage/time converter (29) is provided for delivering a time signal dependent on the amplification control voltage to the control input of the logic switch circuit (26). Signal transmission device in sounding equipment. 19. Front electronic device (14) to amplifier (24). Claims 17 and 17 include an amplification regulator (28) for delivering an amplification control voltage that adjusts the level of the envelope signal (Un; 'H) to a predetermined value. k is a signal transmission device in the ultrasonic sounding device according to item 18. The control unit (20) generates a first synchronization pulse (lJA) at the beginning of the first segment time CT,1) of each transmission period (TP) in synchronization with the generation of the high frequency transmission signal.
;IA) via the connecting line (15) through the logic switch circuit (26) t- and at the beginning of the second segment time ("'I"2) of each transmission period (TP). , 2nd PI period"rus (Uo:, 1o) is transmitted via the connection line (15) k to the logic switch circuit (26) 1
Claims 15 to 19 triggering through
A signal transmission device in an ultrasonic sounding device according to any one of the preceding paragraphs. 21. In the evaluation device (16) at least one control signal (Us) is transmitted during a predetermined time window (Tp) in the second segment time (TF2) of each transmission period (TP). A device (73) for energizing the connecting line (15) is provided and a front electronic device (14)
control signal (US) during a predetermined time window (TF) in each transmission period (Tp) in
Any one of claims 15 to 20 is provided with a detector circuit (50) responsive to the occurrence of
A signal transmission device in the ultrasonic one-sound sounding device according to paragraph 1. 22. The device for applying at least one control signal (IJHI) is connected to the connecting line (1
5) Connect the connecting wire (15
22. The signal transmission device in an ultrasonic sounding device according to claim 21, further comprising a switch (73) for enabling an electric current to be applied to the ultrasonic sounding device. 23. The ultrasonic acoustic device according to claim 22, wherein the connection @(+5) is connected as a current loop to the output side of the current drying nozzles (40) arranged in the front electronic device (14). Signal transmission device in sounding equipment. 24. In the front electronics (14), the detector circuit (5
The amplification control voltage that depends on the output signal of the amplifier (2)
4) A signal transmission device in an ultrasonic acoustic sounding device according to any one of claims 21 to 23, wherein an amplification control circuit (60) is provided.