SU789962A1 - Method of digital recording of seismic oscillations - Google Patents

Description

(54) METHOD FOR DIGITAL RECORDING OF SEISMIC VIBRATIONS

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The invention relates to recording vibrations in seismic exploration.

A known method of reproducible recording of seismic signals, a method of intensity and variable width on 5 magnetic tape and photocarriers to analog form, which means that analog electrical signals are converted into discrete light pulses and recorded on a non-mobile photon oscillator. Discrete or extremal values from the output of a computer or other processing devices are fed to light-emitting devices (for example, light-emitting diodes), combined into one common unit and installed on photosensitive on the surface of the still photo carrier along the recording path

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The disadvantages of this method are the impossibility of directly reading the recorded signals in digital form without the use of intermediate transformations, as well as the distortion of the signals during the recording and reproduction, the increase in ur / vn noise compared to the digital recording that is now widely used .thirty

The closest in technical essence to the present invention is a method of digital recording and input of seismic information in a computer, in which signals are encoded and the resulting parallel, sequential or mixed codes are used for modulating light strokes using the on / off principle and recording these strokes on a carrier, for example, on a buffer data storage device (magnetic tape). A large number of seismograms are recorded on the buffer memory, and the recording is made independently of the computer. After that, information about the times of arrivals and phases of seismic waves is read from the accumulator into the memory of the computer 2j.

The disadvantages of this method are the impossibility of directly reading the signals recorded on the carrier simultaneously in digital and analog form from a fixed carrier, which is important for using optical methods for processing seismic information, as well as the same probability of large and small distortions of signals during recording and reproduction the disappearance of individual completely identical (Discharge or sign pulses recorded on a carrier. Thus, the digital method used in seismic exploration Recording on magnetic and photocarriers allows one to directly enter data into digital computers for processing, but does not directly enter data from those carriers into analog optical processors. On the other hand, analog recording methods allow direct input observational data to optical processors, but do not provide for the exchange of information with digital machines. The last drawback is especially significant if it is necessary to process more and more widely used digital Apis analog optical processor, as it requires additional dubbing of digital seismograms in analog form. This is associated with an increase in the level of interference and additional material costs. The purpose of the invention is to provide readability of the recorded signals in both digital and analog form and to increase the reliability of the recording. The goal is achieved by converting the registration codes of the direct codes of one of the polarities into the reverse ones and controlling the light flux with them, recording the latter on the photo carrier (later we consider a new recording method with respect to photo carriers, although in principle it is also implemented on a magnetic medium), to form strokes, the areas (length, width) of which are proportional to the weights of the corresponding digits of the digital code, to transfer the sign of the signal form a semi-double stroke, the area of which It is proportional to the sum of the weights of all bits of the mantissa. To protect against spurious illumination, when reading in analog form, a black border is drawn at the edges of the signal recording, covering along with the sync pulses separating each following code from the previous one, recording each code from all sides. FIG. 1 shows a parallel code entry; in fig. 2 - sequential; in fig. 3 - two variants of mixed (parallel-sequential) recording by the proposed method. The device for performing the proposed method contains bit strokes 1-4, clock pulses 5, strokes of sign bit 6, and a protective (blackened) border 7. The proposed method of digital recording of seismic signals is performed as follows. The recorded signals, as usual, are represented in the form of n-bit codes (one bit is sign, and the remaining n-1 bits are mantissa). Then, it is converted into a reverse code, which modulates the light fluxes (on / off), applied to the carrier in areas of different bits. Modulationally according to any required law (Fig. 1 and 3). It is easy to implement, for example, using a special bit mask (orifice), the holes in which are arranged in accordance with the code writing scheme, and the area of the holes corresponding to different strokes is proportional to the weights of the bits. (the hole area of the sign bit is equal to the sum of the areas of all the holes of the mantissa bits). Lighting kakhsdo hole pulsed light source. (LEDs, gas discharge lamps, etc.), controlled by the reverse counting code, we get records (figs 1 and 3) on which the black lines on the counter code correspond to black lines and transparent ones to zero. Similarly, the sign bit starts at negative numbers and is transparent at positive numbers. If now the carrier is illuminated, the luminous flux passing through it is delayed by the blackened elements and. It is transmitted transparently, to which the light does not fall on when recording and which, obviously, correspond to the units of the direct mantissa code and the sign plus the signal readout. The luminous flux passed through the carrier during playback, taking into account the proportional area of the areas of the bit elements, weighs) the code bits are: n-1 n-1 H V3H 1 i.-Pi 1Г1 S-lISI where: K O or 1; S is the area of the element for the least significant bitJ R.- the weight of bits (for binary code, 2,4,8 ...); n is the number of code bits (taking into account the sign bit); 1 - luminous flux for - low-order bit. Consider a negative count (blackening of the sign element) with the mantissa 1001 (reverse code IT). Then KO 1, 1, Ki Кз О, i.e. the elements corresponding to the first and fourth orders will be blackened, and the second and third will be transparent. Then the luminous flux transmitted through the carrier is i.0 (1 + 2 + 4 + 8) Slo (0.1 + 1.2 + 1.4 + 0.8) b Slo- (2). Similarly, with a negative sign of the same signal, we have (1 + 2 + + 4 + 8) (0.1 + 1.2 + 1.4 + 0.8) Slg (15 + 6) Stj, (3). Level zero corresponds to the luminous flux 1 1551o. If there is no sign bit in the recording format, it is necessary to apply an electrical offset of the negative signals to the positive region before converting them to a digital code. As can be seen, the luminous flux passing through the photo-carrier in the region where the code of one reference is recorded is proportional to this code taking into account the sign. It should be noted that in order to read the signals recorded in the preraivUM method in digital form on a photo carrier, 9 analogue form requires only a parallel beam of light rays. Consequently, the signals on the record are easily readable visually (through the light), as well as from a fixed carrier, right away along its entire length or at any desired interval. It is also obvious that the record in question is easily readable in digital form, for example, using the same mask as in the recording and the matrix of photocells installed against the opening of each section. A positive feature of the proposed recording method is that the dimensions of the elements (holes) corresponding to the various bits increase with the weight (number) of the bit. As a result, the reliability of reading (and writing) of higher bits is higher than that of younger bits. Accordingly, the level of interference is lower, since the probability of loss and distortion of the most significant bit is always less than that of the lower bit. Blackened around each element of the recording border (code), consisting of two strips running along the recording, and sync pulses 5, excludes errors in amplitudes when reading signals in analog form. Records by parallel and sequential codes do not exhaust all possible options for the placement of code bits during digital recording by the proposed method. In mixed (parallel-sequential) placement of code bits, the element of the symbolic or higher bit (in circuits without a character bit) is located perpendicular to the elements of the other bits. In circuits without a sign bit, the signals are electrically shifted by the magnitude of the zero signal. When recording a number of signals proposed by the method simultaneously on parallel tracks of the carrier, multichannel recording is realized. Along with this, the signals of different channels are behind (written in split mode and on a single track. Claims 1. A method for digitally recording seismic vibrations in which signals are encoded and the resulting parallel, sequential or mixed codes are used to modulate light strokes on the basis of is turned off and these touches are recorded on a medium different from Tei, which, in order to ensure the reading of the recorded signals in both 1T1-frame and analog form and to increase the reliability of the recording, is converted Search for one of the polarity codes of the signals into the reverse codes, modulate the received light streams with all the received codes and form light strokes of them, the cross-sections of which are set proportionally to the weights of the corresponding digits of the digital code of the mantissa number to be written, and for the digit discharge - proportional to the sum of the weights of all the digits of the mantissa. 2. The method according to claim 1, characterized in that, in order to improve the noise immunity, when reading a digital recording in analog form and during multi-channel recording, they are applied to Western There are blackened lines on both sides of each information track. Sources of information taken into account in the examination 1. The author's certificate of the USSR 409i70, cl. Q 01 V 1/24, 1972. 2. Author's certificate of the USSR 221954, cl. G 01 V 1/28, 1966 (prototype).

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Claims (2)

Claim 1. The method of digital recording of seismic 15 oscillations, in which they encode signals and use the obtained parallel, serial or mixed codes to modulate light strokes according to the on-off principle and record these strokes on a medium that differs τεΐ4, which, in order to ensure the reading of recorded signals in both digital and in analogue form and the behavior of recording reliability, they convert the strands of the signal code of one of the polarities obtained during registration into inverse codes, modulate the bit light fluxes with all the received codes and form of their light 30 strokes, the cross-sectional areas of which are set in proportion to the weights of the corresponding digits of the digital code of the mantissa of the recorded number, and for the sign digit, in proportion to the sums of 35 weights of all the mantissa digits. 2. The method according to claim 1, characterized in that in order to increase the noise immunity when reading a digital recording in analog form and with 40 multichannel recordings are applied to the recording on both sides of each information track black lines.