SU1350642A1 - Device for electric prospecting - Google Patents

Abstract

The invention relates to electromagnetic research methods and can be used for electrical prospecting of anomalous inclusions in non-conducting and weakly conducting media for detecting utilities and the like. The purpose of the invention is to increase the sensitivity and performance. For this purpose, the device contains a reference oscillator, two frequency dividers, a periodic signal generator, an emitter, an electromagnetic field receiver, a preamplifier, a zero detector, five single-oscillators, a B-trigger, three AND circuits, an OR circuit, two pulse counters, three decoders, two RS triggers, an inverter, a digital storage unit, a digital-to-analog converter, a measurement and recording unit. The device measures the phase shifts i between the reference signal and the signal occurring in the electromagnetic field receiver. The emitter generates a variable electromagnetic field, which is received by the receiver. The signal from the receiver is amplified by the pre-amplifier, and the zero detector produces pulses at the moment that the signal passes through zero. These pulses trigger a pulse counter that counts the number of pulses of the reference generator in time - between pulses, corresponding to the zero passes of the information signal and the reference one. This number of pulses is a measure of the phase shift. 3 il. with (/) SAE SL About O: y

Description

The invention relates to electromagnetic research methods and can be used for electrical prospecting of anomalous inclusions in non-conducting and weakly conducting media, for detecting engineering communications, etc.

The purpose of the invention is the sensitivity and performance of the device.

FIG. 1 is a block diagram of the device i in FIG. 2 and 3 - timing charts, illustrating the operation of the device.

The device for electrical prospecting consists of the reference generator 1, the first frequency divider 2, the periodic signal generator 3, the emitter 4, the electromagnetic field receiver 5, the preamplifier 6, the zero detector 7, the third one-oscillator 8, the D-flip-flop 9, the second 10 and the third 11 schemes AND, schemes OR 12, second counter 13 pulses, first 14, second 15 and third-16 decoders, fourth 17 and fifth 18 single-oscillators, first 19 and second 20 RS-triggers, second frequency divider 21, inverter 22 eg the second, 23 and the first 24 one-shot, the first circuit AND 25, the first pulse counter 26, the digital storage unit 27, the digital-analog converter 28 and the measurement and recording unit 29.

The device works as follows.

The generator 1 generates pulses and high frequency f (Fig. 2). These pulses arrive at the first frequency divider 2 with a division factor of N, which is chosen so that the frequencies f g following impulses at the output of the divider 2 fall within the frequency range of the electrical installation (from ten to hundreds of hertz). f f / N, Pulses from the output of divider 2 frequency excite at frequency f ,, a generator of 3 periodic signals, the current of which I (Fig. 2) feeds the radiator 4,

The receiver 5 converts the electromagnetic field into an alternating electrical voltage Uj with a frequency fp (Fig. 2). This voltage, after being amplified by the preamplifier 6, is fed to the detector 7 zero. Square pulses and from the output of the detector 7 are fed to the third one-shot 8, which forms short pulses Ug, coinciding with the fronts of the pulses and. These pulses arrive at the synchronization input of the D-flip-flop 9 and the second circuit AND 10. The counters input of the second counter 13 pulses receives pulses from the output of the reference oscillator 1. Conversion factor

The second counter 13 pulses is chosen large N. Three counters 14-16 are connected to the counter output. The first decoder 14 registers the state of the counter 13, corresponding to the number

five . The pulse U is used to set the state of the D-flip-flop 9 and the state 1 of the first RS-flip-flop 19. The second decoder 15 generates pulses when

0 when the second counter reaches 13 pulses of a state corresponding to a number.

To the output of the second decoder 15 is connected to the fourth one-shot 17,

5 which serves to shorten the pulses. The shortened pulse U ,, (figure 2) is fed to the input of the installation in About the first RS-flip-flop 19 and the input of the installation in 1 of the second RS-flip-flop

0 20. At the same time, at the output of the first RS flip-flop 19, a pulse of duration (y2) / fo is formed. At the output of the third decoder 16, a pulse appears at the moment when the counter 13 reaches a state corresponding to the number, the fifth one-shot 18, which shortens the pulses, is connected to the output of the third decoder 16. Shortened impulse u enters

0 is set to O of the second RS flip-flop 20. At the output of this flip-flop, a strobe pulse is generated.

If the phase modulation of the input signal is insignificant or narrow, then the pulse at the output of the third

0

five

.g matching

the one-shot 8 U moment of crossing the zero of the input signal, falls into the time interval of the strobe-pulse from the output of the second RS flip-flop 20 Ujo. Both pulses arrive at the inputs of the second circuit AND 10, therefore, the output of this circuit also contains a pulse corresponding to the 1st temporary position of the pulse Ug (Fig. 3). The output of the second circuit AND 10 is connected to one of the inputs of the circuit OR 12, the output of which also has this pulse. With the circuit code OR 12 pulse i

It enters the installation of the second counter of pulses 13 in the O, which from this moment resumes its operation.

In the event that the phase modulation of the input signal is wideband, that is, the rate of change of the initial phase is significant, the pulse from the output of the third 8 Ug single-oscillator does not coincide in time with the strobe pulse. Then at the output of the second circuit And 10 pulses are missing-. If the pulse and J appears before the pulse U, (FIG. 3), then D-flip-flop 9 triggers, because the Ug pulse arrives at the synchronization input of D-flip-flop 9, while the information input of the same flip-flop is present high logic level and from the output of the first RS flip-flop 19. When D-flip-flop 9 is triggered, a high logic level from its output goes to the first input of the third circuit 11, to the second input of which a pulse is given and, from the output of the fourth one-oscillator 17. This pulse passes at the output of the third circuit And 11 and further to the output one OR circuit 12. Thus, if the next input pulse appears earlier than the strobe-pulse U, j5, then the input pulse is replaced by the pulse U, which coincides with the beginning of the strobe-pulse. The pulse from the output of the OR circuit 12 sets to zero the second counter of 13 pulses, and it starts its operation this time not from the moment of arrival of the next input pulse Ug, but from the moment of arrival of the pulse U,. Thus, the rate of change of the initial phase of the input signal is limited in advance.

If the input pulse Ug arrives later than the strobe pulse Ujo (FIG. 3), then the outputs of the second 1U and third 11 circuits And there are no pulses and the CM 12 circuit receives a pulse from the output of the 18-one single vibrator. Now the second counter of 13 pulses starts counting from the moment it arrives.

pulse and

18

Thus, the growth rate of the initial phase of the input signal is limited to the delay side.

Thus, the conversion factor of the second counter is 13 pulses

350642

varies with the time position of the input pulse U.

relatively strobe pulse U.. If the pulse Ug arrives earlier than im0

five

0

five

0

five

five

0

pulse and, then the coefficient of recalculation of the counter 13 is equal. If the pulse Ug coincides with the pulse, then the coefficient of the counter 13 is equal to N ,. In the case when the pulse Ug arrives later than the strobe pulse U, the counter 12 operates with a conversion factor N. +1.

In this case, the rate of change of the initial phase of the input signal is limited. By appropriately selecting the frequency of the reference oscillator and the coefficient N., the necessary bandwidth of the device can be obtained.

From the output of circuit 1WH 12, the pulses arrive at the second frequency divider 21, the division factor N. of which is chosen such that the period of the pulses at the output of the second divider 21T and NL Tf does not exceed half the minimum duration of the information anomalous signals. The interval between pulses at the output of the second frequency divider 21 is equal to the period of the input pulses T. The first input of the AND 25 circuit is supplied with voltage from the output of the second divider 21, and to the second from the output of the reference generator 1. At the cxeMi i output, 25 pulses of the reference frequency f are present only during the action of pulses from the divider 21. When the output pulse of the divider 21 appears, the first Q one-oscillator 24 generates a short pulse, which is fed to the input of the zero setting of the first counter of 26 lp pulses. The latter is set to the state O, after which the counting of the pulses of the reference frequency fg, arriving at its counting input from the output of the first circuit AND 25, begins. Thus, the measurement of the time I p of the terminal t T (Nj-1) takes place. The state of the counter 26 at the end of the inter5

The shaft t carries information about changes in the initial phase of the input signal that have occurred during time t. After the end of this interval, the second one-shot 23, the input of which receives the pulses inverted by the inverter 22 from the output of the divider 21, generates a pulse arriving at the control input of the digital unit 27

memory Thus, in memory 27, the contents of counter 26 are copied. From the output of memory 27, information is fed to a digital-to-digital converter 28, where it is converted into a similar form. The analog voltage from the output of the converter 28 is supplied to the measuring and recording unit 29.

Claims (1)

Invention Formula A device for electrical prospecting containing a series-connected reference generator, a first frequency generator, a periodic signal generator and an emitter, and a receiver of an electromagnetic field connected to the input of a preliminary amplifier, detector-zero, a second frequency divider, a voltage inverter, the first and the second one-shot, the first And circuit, the first pulse counter and the series-connected digital storage unit, the digital-analog converter and the measurement and recording unit, the first input of the first cf We are connected to the output of the reference oscillator, the second frequency divider is connected to the second input of the first I circuit, to the input of the voltage inverter and to the input of the first one-oscillator, the output of the first AND circuit is connected to the counting input of the first pulse counter j, the output outputs of which are connected to the inputs the digital memory unit, the output of the first one-shot is connected to the input of the first pulse counter in O, the output of the voltage inverter is connected to the input of the second one-shot, the output of which is connected to the control input of the digital memory unit, characterized in that, in order to increase the sensitivity 0 as well as performance, the device additionally contains the third, fourth and fifth single vibrators, B trigger, second and third AND schemes, OR circuit, second pulse counter, the first, second and third decoders, the first and second RS triggers, and the preamplifier output is connected to the detector input zero, the output of which is connected to the input of the third one-oscillator; the output of the third one-oscillator is connected to the first input of the second And circuit and the counting 5 input of the D-flip-flop, the output of which is connected to the first input of the third And circuit, O The second and third AND circuits are connected to the first and second inputs of the OR circuit, the output of which is connected to the c4eTHbLM input of the second frequency divider and to the initial setup input of the second pulse counter, whose counting input is connected to the output of the reference generator, and the output outputs are connected to the inputs of the first The second and third decoders, the first decoder is connected to the installation input of the D-flip-flop and to the installation input of 1 of the first RS-flip-flop, the output of which is connected to the information input of the D-flip-flop, the second decryptor It is connected to the input of the fourth one-vibrator, the output of which is connected to the installation input of the first RS trigger, the installation input of the second RS flip-flop and the second input of the third circuit And, the output of the third decoder is connected to the input of the fifth one-oscillator connected to the input of the setup in the second RS-- trigger and the third input of the OR circuit, and the output of the second RS trigger is connected to the second input of the second circuit. And, five Q five 0 five FIG. 7 V, S u P and. rrf and s 20Un P Tl P u  eight I and, n / J Fie.2  t  t Compiled by A.M. Gkov Editor I.Nikolaychuk Tehred L.Oliynyk Proofreader S.Shekmar Order 5283/47 Circulation 730 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and Printing Enterprise, Uzhgorod, st. Project, 4 g /,  yy 07.5