SU894648A1 - Measuring instrument for electric geogurvey - Google Patents

Description

(54) MEASURING DEVICE FOR GEOELECTRIC EXPLORATION

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The measuring device for geoelectromagnetic exploration is intended for the search for polarizing objects by the method of induced polarization at low frequency alternating current.

A device for amplitude and phase measurements is known, comprising a high frequency generator, a coding block, a result accumulation block, registers of the previous and subsequent layers, a comparison block, registers of a specified error and a specified number of matches. This device eliminates non-repeating counts 1.

The disadvantage of the device is low noise immunity when working with selective amplifiers due to long transients in selective amplifiers. In addition, this device is designed so that if its input receives the correct readings not more than once, but through one, then all samples are not skipped, and vice versa, two identical consecutive wrong samples are skipped.

Measuring devices for geo-surveys are also known.

containing input device, i.biralnye amplifiers, drivers, phase meter device and display device. These devices allow phase and amplitude measurements on alternating current.

The disadvantage of these devices is low noise immunity.

10 when exposed to transient interference.

Closest to the present invention is a measurement setup comprising an input device, retrofit amplifiers, a phase metering device, an indication unit, and an averaging counter. Measuring installation of the station INFKZ-VP has all the immunity when exposed to stationary interference, so

20, as in this device, the determination of the phase shift is performed not for one but for several periods of the signal being measured, and the number of averaging periods is set by the operator C3.

The disadvantage of this measuring device is low immunity when exposed to non-stationary interference. After exposure to non-stationary interference in the selective amplifiers, transients begin, the duration of which is determined by the quality factor H36HpaTo. amplifiers and interference parameters. Do transients in the display unit of the measuring device receives incorrect information, which appears as scatter between individual readings. Reducing the duration of transients by reducing the quality factor of selective amplifiers leads to a decrease in the measurement accuracy due to the penetration of interfering frequencies into the signal.

The purpose of the invention is to improve noise immunity.

The goal is achieved by the fact that in a known device, consisting of an input unit, selective amplifiers; the outputs of which are connected to the input.m of the forgators, the outputs of which are connected to the inputs of the phaseometric device, the output of which is connected to the input of the display unit, the nonlinear filtering unit is entered, the input of which is connected to the input input unit, and the output of the nonlinear filtering unit is connected to the inputs of the selective filters.

A non-linear filtering block is a systoct from a quantizing block, a difference block, four groups, keys, a memory block, a decoder, a counter, a clock generator, a scanner circuit, an averaging block and a matching block, and the information input of the quantizing block is an input of the block non-glue filtering and connected to the output of the input unit, and the output of the quantization unit is connected to the information inputs of the keys of the second group and to the first input of the difference unit, the code of which is connected to the first input of the comparison circuit and information input With the keys of the third group, the outputs of which are connected to the corresponding, to the inputs of the averaging unit, the outputs of which are connected to the information inputs of the keys of the fourth group, the outputs of the latter are combined and connected to the second input of the comparison circuit, the output of which is connected to one of the inputs of the decoder, the remaining inputs of the decoder connected to the codes of the counter, the input of which is connected to the output of the clock pulse generator and the control input of the quantization unit, and the outputs of the decoder are connected to the control inputs of the keys first, second, third and fourth groups, and the outputs of the keys of the second group are connected to the inputs of the memory unit, the outputs of which are connected to the informational inputs and the keys of the first group connected by their outputs to the second input of the difference unit and the input matching unit whose output is the output of the nonlinear unit filtering and connected to the inputs of selective amplifiers.

The drawing is a block diagram of the device.

The device contains an input unit 1, the output of which is connected to the input of the nonlinear filtering unit 2, and the output of the nonlinear filtering unit 2 is connected to the inputs of selective amplifiers 3 and 4, the outputs of which are connected to the inputs of the driver 5 and the outputs of which are connected to the inputs of the phaseometric device 7, the output of which connected to the input of the display unit 8. The nonlinear filtering unit contains a quantization unit 9, whose information input is the input of the nonlinear filtering unit and connected to the output of the second block, and the output of the quantization unit 9 is connected to the information inputs of the keys 10 of the second group and to the first input of the difference unit 11, the output of which is connected to the first the input of the comparison circuit 12 and with the information inputs of the keys 13 of the third group, the outputs of which are connected to the corresponding inputs of the averaging unit 14. The outputs of the averaging unit are connected to the information inputs of the keys 15 of the fourth group, the outputs of which are combined and connected to the second input of the circuit and the comparison, the output of which is connected to one of the inputs of the decoder 16. The remaining inputs of the decoder are connected to the outputs of the counter 17, whose input is connected to the output of the generator 18 clock pulses and control input of the quantization unit. A group of outputs of the decoder is connected to the intertwined control inputs of keys 19 of the first, 13 third and 15 fourth groups. The second group of outputs of the decoder is connected to the control inputs of keys of the second group, the outputs of which are connected to the corresponding inputs of memory block 20. The outputs of the memory block 20 are connected to the informational Inputs of the keys of the first group. The outputs of the keys of the first group are connected to the second input of the difference unit and to the input of the matching unit 21, the output of which is the output of the nonlinear filtering unit and connected to the inputs of the selective amplifiers.

Claims (3)

The input unit 1 serves to match the input signal with the remaining blocks of the circuit and may contain an attenuator and a preamplifier. The quantization unit 9 serves to time the quantization of the signal. It is clocked by the clock pulse generator. The quantization unit provides the average voltage value per conversion cycle. In the case of performing blocks 1021 based on digital elements, the quantization block 9 should contain an analog-to-digital converter. The memory unit 20 serves to store the samples received from the quantization unit 9. The difference block 11 serves to obtain the modulus of the difference between the samples from the quantization unit 9 and the first group of keys 19. The comparison circuit 12 serves to compare the signals arriving at its inputs. When a signal is received from block 11 of a difference greater in level by a predetermined value than the signal coming from averaging unit 14, the comparison circuit 12 must produce a inhibitory signal. The averaging unit serves to average the signals from the difference unit 11. The matching unit 21 serves to convert the code into an analog signal. In the case of execution of blocks 9-15 and 19, 20 based on analog elements, block 21 is not needed. The measuring device for geo-electrical exploration works as follows. The input signal in input block 1 is normalized in amplitude and fed to a quantizing unit, where it is time-quantized. The quantization step is determined by the required accuracy and is set by the clock pulse generator 18. The number of discrete samples for one period of the measured signal is N -, where T is the period of the measured signal. At is the quantum step. Discrete samples, proportional to the average for the time d1 of the input signal, go to the information inputs of keys 10 of the second group and to the input of difference block 11 When each new sample arrives from quantization unit 9 simultaneously using keys 19 of the first group controlled by counter 17 via a decoder 16, a new cell of the memory block 20 is fenced (the number of cells is N) and a new readout from the memory block 20 is received at the second input of the difference block 11. If the samples recorded in memory block 20 are different from the samples received from quantization unit 9 (this may be the case, for example, at the beginning of measurements), then the difference modulus at the output of the difference unit may have a value greater than the set value specified in circuit 12 The difference module is fed to the first input of the comparison circuit 12 and through the keys 13 of the third group to the input of the cell of the averaging unit 14, where the average value between the samples obtained for the previous period is calculated (in our example, they are equal to zero) and again them. The output of the cells of the averaging unit 14 through the corresponding keys 15 of the fourth group is fed to the second input of the comparison circuit 12. If the difference between the difference module and the signal at the output of averaging unit 14 is greater than the value of the predetermined threshold in the comparison circuit 12, then the output of the comparison circuit 12 results in a inhibitory signal that is fed to the input of the decoder 16. In this case, the decoder 16 does not generate a signal the opening keys 10 of the second group and the samples recorded in the cells of the memory unit 20 do not change. With each new input period, the output of the cells of the averaging unit 14 increases. After three to four periods, it becomes comparable with the difference modulus, and the output signal disappears at the output of the comparison circuit 12. Thereafter, at the end of the quantization clock, the output of the decoder 16 corresponding to this sample appears a unlocking signal, and the sample received from quantization unit 9 is recorded in the cell of memory unit 20. Thus, discrete samples for the entire period of the measured signal will be recorded in the cells of the memory block 20. If there is no transient interference, then each sample of subsequent periods of the input signal is close in magnitude to the corresponding sample recorded in the cell of memory block 20 and at the output of differential block 11 there will be a signal close to zero. (The magnitude of this signal is determined by the fluctuation noise and noise of the circuits) At the output of the cells of the averaging unit 14 (these cells are polled simultaneously with the cells of the memory unit 20 by the counter 17 via the decoder 16), the output signal decreases and after 3-4 periods becomes close to the magnitude of the difference . Thus, at the moments when there is no interference in the cell of the memory block 20, record samples representing the measured signal with sufficient accuracy and prepare for the arrival of the interference of the cell of the averaging unit 14. In the case of the arrival of non-stationary interference, the samples received from the input unit are very different from the samples recorded in the previous period, which are received from the memory unit 20. At the output of the difference block 11, a signal appears whose magnitude is equal to the amplitude of non-stationary interference and the comparison circuit 12 generates a inhibitory signal. In this case, no control signals are generated at the output of the decoder 16 to unlock the keys 10 of the second group, i.e. the interfering signals received from the quantization unit 9 will not be recorded in the flea cells; 20 memories and in these cells remain predictive samples. Since the outputs of the selective amplifiers 3 and 4 do not come from the input unit 1, but from the memory block 20, then the non-stationary space will not be received through the matching block to the input of the selective amplifiers. This is how non-stationary interference is filtered and long transients in selective amplifiers due to non-stationary interference are eliminated. Further signal processing is performed as in known devices. The output signal from the output of the selective amplifiers 3 and 4 is fed to the inputs of the formers 5 and 6, the outputs of which are connected to the input of the phase metering device 7 (the number of selective amplifiers may be different, for example, three selective amplifiers should be used for three-frequency measurements). From the output of the phase meter device 7, information is supplied to the display unit 8. In the proposed measuring device for geoelectromagnetic exploration, nonlinear filtering of the input signal is carried out, which makes it possible to decrease or completely eliminate (depending on the parameters of the interference, the effect of non-stationary interference. Claim 1. Gauge measuring device for geoelectromagnetic, containing the input unit, selective amplifiers, BHXojEtH which are connected to the inputs of the formers, the outputs of the formers are connected to the inputs of the phase of the KOfo of the device, the output of which is connected to the input of the indication unit, in accordance with This is because, in order to improve noise immunity, a nonlinear filtering block was inserted into Hetxj, connected between the input device and selective amplifiers. 2. The device according to claim 1, is only because the nonlinear filtering unit contains a quantizing unit, a difference block , four groups of keys, a memory unit, a decoder, a counter, a clock pulse generator, a comparison circuit, an averaging unit and a matching unit, the information input of the quantizing unit being the input of the nonlinear filtering unit and connected to the output of the input unit, and the output of the quantization unit is connected to the information inputs of the keys of the second group and to the first input of the difference unit, the output of which is connected to the first input of the comparison circuit and the information inputs of the keys of the third group, the outputs of which are connected to the corresponding inputs of the averaging unit, the outputs of which are connected to the information inputs of the keys the fourth group, the outputs of the latter are combined and connected to the second input of the comparison circuit, the output of which is connected to one of the inputs of the decoder; the remaining inputs of the decoder are connected the counter outputs, the input of which is connected to the output of the clock generator and the control input of the quantizing unit, and the outputs of the decoder are connected to the control inputs of the keys of the first, second, third and fourth groups, and the outputs of the keys of the second group are connected to the inputs of the memory block whose outputs connected to the information inputs of the keys of the first group, connected by their outputs to the second input of the difference unit and the input of the matching unit, the output of which is the output of the nonlinear filtering unit and connected to the input s selective amplifiers. Sources of information taken into account in the examination 1. The author's certificate of the USSR 646292, cl. G 01 V 3/06, 1978. 2. USSR author's certificate for application number 2703183 / 18-25, 1978. 3.Kulikov A.V. et al. Phase measurements in the AC method on alternating current. Alma-Ata, 1975, p. 55-59 (prototype).