SU890329A1 - Electric geosurvey meter of signals - Google Patents

Description

This invention relates to exploration using alternating current and is intended to search for polar-ri. Objects with the method of induced polarization on alternating current using three frequencies.

Three-frequency electric probes of sigals are known, in which for the separation of polarization and induction effects, measurements can be performed simultaneously on three frequencies, containing three selective amplifiers, three formers, a frequency multiplier, a frequency divider, triggers, and an indication unit. This device is designed to work with a three-frequency trigger generator. The device's selective amplifiers are tuned to the frequencies Wi, uij, uj, and the ratio 20

g

Wji

schrn - integers. The device performs frequency conversion to the frequency uj (j, which allows

for each half-period to form not one, but B time intervals, for which, by averaging, the accuracy can be improved

A disadvantage of this device is the use of a frequency divider, the presence of which does not allow to measure all the moments of crossing the zero frequency w, which leads to a loss of accuracy. In addition, a frequency multiplier is connected between the selector1 1 amplifier and the driver. Because of this inclusion, the multiplier is made in the form of an analog device containing selective amplifiers, which leads to additional errors and a considerable complication of the design.

Also known electro-intelligence Hbrii signal meter, which contains three selective amplifiers, three shapers, two triggers, a clock pulse generator, two keys, a unit of computation and display. Device

It works in conjunction with a generator set that produces a current whose shape is close to rectangular. The selective amplifiers of a three-frequency measuring device for electrical survey are extracted from the signal of the first, third and fifth harmonics 23.

The disadvantage of this device is that during the first half period of the first harmonic only two time intervals are formed, one of which corresponds to the time between zero transition times from the outputs of the first and third harmonics, and the second interval of the fifth and third . The presence of side penetrating harmonics in the output signals of the selective at the dalitel leads to systematic error, since the time interval is formed not at the moment of the transition through the zero of the corresponding harmonic, but at the time of the transition through the zero of the sum of the voltages of this harmonic and penetrated by their signals, In the output signals of the selective amplifiers Signals are also caused by noise from the input device and interference. The presence of these signals leads to the appearance of a random error, which is in the form of scatter. Especially, one-third and one rapMoimioi are affected by noise and interference, whose amplitudes in the input signal are much smaller than the first.

The purpose of the invention is to improve the accuracy and performance of measurements. The goal is achieved by the fact that in an electrical prospecting signal meter for a geoelectrical substation, there are three selector amplifiers, the outputs of which are connected to a pulse shaper, a frequency multiplier, a digital conversion unit, including two flip-flops, with their inputs connected to the outputs respectively, the second and third pulse shapers, and the outputs - each, respectively, to his own. Well, the key, the outputs of which are connected to two inputs of the computing unit loaded with the display unit, while the pulse clock generator is connected to the second key inputs, the frequency multiplier is connected between the output of the pulse driver and the second input of the first trigger, and

parallel to it, a second frequency multiplier is turned on, the output of which is also connected to the second input of the second trigger.

Pa figure 1 shows a diagram of the electric meter; on (} mg.2 time diagrams №1 (h, 5,8,1,, е, е, ж, з и, к, l, m, explaining his work. The device contains selective amplifiers 1,2 and 3, the inputs of which are connected to the input of sensors (not shown), and the outputs are connected to the inputs of pulse shapers 4.5 and 6, moreover, the output of the first pulse shaper is connected to the inputs of the digital conversion unit 7 containing the first 8 and second 9 frequency multipliers, first trigger 10 , the second trigger 1, the clock pulse generator 12, the first 13 and the second 14 keys, the informational inputs of which are connected to the clock generator output pulses, and the outputs of the keys 13 and 14 are connected to the input of the computing unit 15, the output of which is connected to the input of the display unit 16.

The scheme (see fig.I) works as follows.

The electric field in the earth is excited by an alternating current generated by a generator set (not shown). For measurement by the method of induced polarization on alternating current, generator sets are used which produce a current,

whose shape is close to the right angle. Such generator sets are much simpler and cheaper than multi-frequency, d

, 2 letters a, 5, t show the signals on the input of amplifiers 1,2 and 3, the letters t ,, in - the signals at the outputs of the formers 4,5 and 6,

letters, and, 3 - pulses at the outputs of frequency multipliers, letters

and, to illustrate the shape of the signals at the outputs of the triggers, and the letters and M on the alkhods of the keys.

Selective amplifiers 1,2 and 3, B14 are separated from the input signal

the first (.9), the third (5) and the fifth (6 harmonics, with the help of formers 4.5 and b, pulses are formed corresponding to the moments of transition of the sinusoids through zero (and, E, c). Impulses

Former shaper 4

the first harmonic is fed to the inputs of frequency multipliers 8 and 9. Frequency multipliers can be performed.

for example, on digital circuits delay. The frequency multiplier 8 on each 1 arriving at its input a pulse from the first harmonic formfinder produces three pulses, the frequency of which is equal to the frequency of the pulses from the third harmonic generator. In order not to use devices that determine the sign of the phase shift, frequency multiplier 8 can form the first pulse not immediately after the pulse arrives from the first harmonic generator 4, but after a time period equal to 1/12 of the first harmonic period (diagram). Frequency multiplier 9 per caldey of the inputs to its input impulse from the primary harmonic generator 4 produces five pulses, and the first pulse is also generated not immediately after the arrival of the pulse from the imaging generator 4, but after 1/20 of the first harmonic period (dAgr). The impulse (2) 1, coming from the output, multiply by 8, sets trigger 10 to one state. The pulses, coming from the output of the former 5, reset the trigger. At 4eir.2, the pulses formed at the output of trigger 10 are shown. The pulse intensity at the alchow of trigger 10 is equal to

T - - tAt,. ,

 - sh - ch-b

where is the period of the first harmonic, the phase shift between the first and

the third harmonic lw, is the frequency of the first harmonic, the time increment due to harmonic penetration and. During the time T, equal to the period of the first harmonic, six pulses of t c are formed (up to the number of half-periods of the third harmonic).

The trigger 11 control ers pulseslet, coming from the frequency multiplier 9 and shaper 6. On fig.2k shows the pulses at the output Q of the trigger P. The power of these pulses is equal to H)

(tSrW t

 - phase shift between the first and fifth harmonics;

(.1-5) time increment due to penetrating harmonics and noises.

During time T, equal to the period of the first harmonic, is formed - ten pulses,

The pulses forked by triggers 10 and P are fed to the control inputs of keys 13 and 14. If there are pulses on the control inputs of keys 13 and 14, the pulses from the clock generator 12 are received at the inputs of the computing unit 15 (A, I 7. Block 15 determines the average for the period Vjk Vsb ", i.e., performs support of the form

6 -. 40

(4-5) i

SH-J) i.

  13

in the computational block} 15, the parameter H is found (the phase shift of the field intensity of the EP relative to the current), which for threefrequency 1x measurements can be calculated, for example,

V iF4i-b)

. where whale scale factors. After calculating the result goes to the display unit 16.

Thus, in the device, not one

. frequency, and to two, more precisely, the first harmonic leads to the third and fifth, which allows to increase the accuracy and performance of the device.

with known alignment is provided by processing all the moments of transition through the zero fifth harmonic. When pachspedii average for the period "-5) tP it turns out & f that the value

} becomes significantly smaller, 4eMAt 5ji. Part 4kl;., Due to the mutual penetration of harmonics, becomes close to zero when summing over the period, and part of

due to shumaksh decreases in W, where ft is the number of samples, i.e. with the average for the period, the error due to noise decreases by about 3 times. Breakdown

hf (the drive stem is provided due to the fact that during measurements it is possible to reduce the averaging value and also due to the fact that

By reducing the effect of mutual penetration of the harmonics, the Q-factor of the selective amplifiers can be reduced.

Claims (2)

1. USSR author's certificate number 327428, cl. G OIV S / S, - 1970. 2. USSR author's certificate according to application No. 2607610 / 18-25, cl. O 01 V 3/10, 1978 (prototype). figure 1