CN1015673B - Frequency spectrum stimulated electricity surveying system with double-frequency channels and multiparameters - Google Patents

Frequency spectrum stimulated electricity surveying system with double-frequency channels and multiparameters

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CN1015673B
CN1015673B CN 88105655 CN88105655A CN1015673B CN 1015673 B CN1015673 B CN 1015673B CN 88105655 CN88105655 CN 88105655 CN 88105655 A CN88105655 A CN 88105655A CN 1015673 B CN1015673 B CN 1015673B
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frequency
signal
circuit
double
low
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CN1034276A (en
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何继善
鲍光淑
任宝琳
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Central South University
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Central South University
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Abstract

The present invention relates to a frequency spectrum stimulated electricity observing system with double frequency channels and multiple parameters, which is suitable for the stimulated polarization observing scheme in the frequency field of geoelectric prospecting. The observing instrument adopts double-frequency composite signal transmission, simultaneous double-frequency reception, direct Fourier transformation for analogue quantities, and other technical measures. The observing instrument has the characteristics that the differences of high frequency and low frequency can be freely selected, multiple groups of different frequency pairs can be formed, and ReL, Reh, phiL, phih, Rs, Sp, Psh, PsL eight observed parameters can be measured once. The instrument has the advantages of portability and little power consumption, and can be used for general surveys and detailed surveys. The present invention is especially suitable for the exploration for complicated terrains.

Description

Frequency spectrum stimulated electricity surveying system with double-frequency channels and multiparameters
The present invention relates in the geophysics electrical method exploration, adopt the observation program of frequency field induced polarization and be applicable to the observation instrument of this scheme.
The induced polarization observation method of frequency field mode, be to the underground exciting current of sending into electrode, and, further utilize the anomaly analysis underground structure of response potential difference (PD) and frequency characteristic appearance from the frequency characteristic that the potential difference (PD) (current potential) that potential electrode obtains comes recording geometry to respond.In the observation program of present several practicalities, a kind of frequency conversion scheme that is is arranged, be the frequency that on same measuring point, changes exciting current, calculating percent frequency effect PFE(is apparent rate of frequency spread Ps), or the amplitude phase place of survey fundamental frequency.The benefit of this scheme is to use better simply transmission, receiving trap, as the IPV-3 spectral excitation polarizer of Canadian phoenix company, is to change line frequency with receiver scan control transmitter, measures multifrequency amplitude phase place.Yet because the signal of different frequency is measured at different time, the job stability of transmitter will influence observed result, as when surveying apparent rate of frequency spread, just the instability of high and low frequency electric current causes the error of apparent rate of frequency spread.And when carrying out spectrum measurement, it is longer to measure the used time of low frequency signal, and to do to measure one by one will be very slow to frequency one by one.
In the prior art, also has a kind of representational odd harmonic scheme, its transmitter sends the square wave electric current of certain frequency, and receiver receives the real component and the imaginary component of first-harmonic and one or more higher hamonic wave (having only the odd ripple) measurement first-harmonic and higher hamonic wave simultaneously.The GDP-12 type complex resistivity instrument of U.S. ZONGE company just belongs to this type.The odd harmonic scheme can realize that multiple-frequency signal observes simultaneously, yet, this also brings a shortcoming that is difficult to overcome, promptly along with the increasing of overtone order, the amplitude of harmonic current is inverse ratio and reduces, and is measuring higher hamonic wave for example during 13 subharmonic, amplitude has only 1/13 of first-harmonic, reach necessary signal intensity and must improve fundamental current, and fundamental current increases considerably and not only causes waste, and transmitting apparatus is increased the weight of.If take the lower harmonic wave of number of times, frequency range is narrowed down, be used to generally investigate the apparent rate of frequency spread or the relative phase difference of required measurement, because of the too for a short time unusually accuracy of observation that causes low.
Purpose of the present invention is to make the excitation current that is sent simultaneously that suitable frequency difference be arranged, and guarantees that again the amplitude of high and low frequency is approaching, and accomplishes the measurement of multiparameter, particularly frequency spectrum on this basis.
Technical scheme of the present invention is: by the square wave electric current of transmitter transmission high and low frequency composite signal, and it is right to obtain the different frequency of many class frequencys through conversion, and the high and low frequency difference of every pair of frequency can be selected arbitrarily; And receiver is directly converted to real component, the imaginary component of high and low frequency with the composite signal that receives with the simulation fourier transform device that is concerned with, and remakes analog to digital conversion, obtains final observed parameter by Computer Processing.
Now further specified:
One. transmitter
Its core is that double frequency forms circuit, mainly is made up of trigger and analog switch.The high-frequency signal that is produced by crystal oscillator obtains the high and low frequency signal of lower frequency through the frequency dividing circuit frequency division, changes the combination of frequency divider, and the low-and high-frequency that can obtain any fixed frequency difference is right with different frequencies.General frequency difference is elected 9 or 13 frequencys multiplication as, frequency between form fairly simple with 2 frequencys multiplication relation.Above-mentioned signal is sent into double frequency and is formed circuit, with the synthetic composite signal of low-and high-frequency, does powerful composite signal output through the one drive circuit control inverter with certain phase place.
Two. receiver
Analog channel.Mainly comprise amplifier and wave filter.Amplifier is made up of a plurality of amplifier stages, to obtain high input impedance (>10M Ω), high gain and big gain-adjusted scope (2 °~2 12).Wave filter comprises power frequency notch filter and low-pass filter.The frequency range of low-pass filter should be greater than the frequency range of transmitter output signal.
The Fournier transform device that is concerned with.This is a functional unit with the analog quantity Direct Transform.To the low-and high-frequency composite signal that receives,, can obtain four parameters through fourier transform respectively with the one-period T of its medium and low frequency:
ReU(ω L)=ω LT oU Two(t) Sin ω Ltdt
ImU(ω L)=ω LT oU Two(t) COs ω Ltdt
ReU(ω h)=ω hT oU Two(t) Sin ω htdt
ImU(ω h)=ω hT oU Two(t) COS ω htdt
Wherein:
ReU(ω L) be low frequency real component magnitude of voltage; ω LBe the low frequency circular frequency;
ImU(ω L) be low frequency imaginary component magnitude of voltage; ω hBe the high frequency circular frequency;
ReU(ω h) be high frequency real component magnitude of voltage;
ImU(ω h) be high frequency imaginary component magnitude of voltage;
U TwoBe the double frequency composite signal; T is the cycle.
Realize by the relevant device of fourier transform fully with up conversion.This functional unit has an analog sine wave producer, if utilize control signal to move 1/4T, can realize that 90 ° of displacements obtain cosine wave (CW).
If composite signal directly is added to the end of going into of sine-wave generator, control it again and be input as a low-frequency cycle, send count pulse simultaneously, just can realize multiplying each other of a low-frequency sine and a low-frequency cycle composite signal, its result sends into low-frequency cycle of integrator integration, obtains Re LIn like manner, can realize multiplying each other of a low frequency cosine wave (CW) and a low-frequency cycle composite signal, obtain Im L
If control is input as a high-frequency signal cycle, send count pulse simultaneously, just can realize multiplying each other of high_frequency sine wave or high frequency cosine wave (CW) and a high frequency period composite signal, its result sends into integrator also needs low-frequency cycle of integration to obtain Reh and Imh.
Microprocessor and interface section thereof.The microprocessor that constitutes parts as receiver can adopt any type in principle, in fact selects one eight single-chip microcomputer for use.Computing machine is also finished following function as control device except as the data processing device:
Modulus or digital-to-analog conversion.Instrument is zero point with the value of a low-frequency cycle of integration, when output valve is non-vanishing, promptly be considered as spontaneous potential SP+ sum at zero point, by system controlled by computer with this value through analog to digital converter conversion back storage, convert analog quantity by interface to by digital to analog converter again and send into amplifier SP+ is compensated zero point.Control high frequency, the real component of low frequency, imaginary component are carried out analog to digital conversion and computing, draw required observed parameter, and are stored, in order to calling.
The synchronizing signal forwarder is to realize high pressure and low pressure isolation, transmits synchronizing signal and gives receiver as measuring basis.
The present invention adopts double frequency transmission, double frequency to receive the mode that processing obtains observed parameter simultaneously, can guarantee accuracy of observation, has avoided making equipment to enlarge the problem that increases the weight of, and has realized the miniaturization of multi-functional sharp electric observation instrument.Available a pair of frequency is done census operations, also can select for use many frequency is done to swash electric spectrum measurement to satisfy the detailed survey needs.
Accompanying drawing 1 is the circuit contact figure of transmitter of the present invention;
Accompanying drawing 2 is the circuit waveform figure of transmitter of the present invention;
Accompanying drawing 3 is the circuit contact figure of receiver of the present invention;
Accompanying drawing 4 is the relevant device electrical schematic diagram of the fourier transform among the present invention;
Accompanying drawing 5 is computer programme flow diagram among the present invention.
One embodiment of the present of invention obtain the support of accompanying drawing.The each several part circuit constitutes and contact is described below:
One. transmitter
Oscillator 1 is a quartz oscillator, and its nominal frequency is 32768HZ.
Frequency dividing circuit 2 and freq converting circuit 3 are made up of 4 asynchronous up counters of C186 arbitrary carry system and 10 d type flip flops.Change wiring by a waver, obtain 9 frequency divisions and 13 frequency divisions, it is right that another waver control forms 8 different frequencies: 0.028/0.25; 0.056/0.5; 3.566/32Hz or 0.019/0.25; 0.038/0.5 ... 2.462/32Hz.
Double frequency forms circuit 4 to be made up of 4 triggers, produces two groups of composite signals (shown in a, b in the accompanying drawing 2), output control Driver Circuit 5, and a taking-up part outputs to this circuit of mark 7.
This circuit of mark 12 is made up of 4 groups of 16 triggers.
Driving circuit 5 is formed current amplifier and emitter follower by 7 transistors, and composite signal is after time-delay, again through emitter follower to a differentiating circuit, after phase inverter is exported control inverter 6 conducting chronologically, e in control waveform such as the accompanying drawing 2, f.Inverter 6 output voltage 400v, d in waveform such as the accompanying drawing 2.
Sampling resistor 8.Measure supply current by sampling resistor 8 and current measurement circuit 9.
First current foldback circuit, 10 setting values are 1.25 times of rated current, and the controllable silicon by a 3CT1KC during overcurrent blocks driving circuit 5 and current switching circuit 7, to cut off major loop.
Second current foldback circuit, 11 setting values are 1.3 times of ratings, by CRS5 conducting short circuit high pressure, insurance are blown during overcurrent, to cut off major loop.
Stabilized voltage supply 13 output+8V and-two groups of voltages of 8V.
Two. receiver
Prime amplifier 14 mainly is made up of CMOS four-operational amplifier, 2 C544 analog switches, 2 phase inverters.Two amplifier parallel connections wherein connect one group of differential amplifier again.Input impedance>50M Ω, gain-adjusted model are 2 0~2 5, control by analog switch.The spontaneous potential SP that exports when system controlled by computer makes preamplification gain KF=1 adds value at preposition zero point, and, become digital quantity by the A/D conversion and in microcomputer, store after low-frequency cycle through zeroing integrator 15 integrations, and through D/A 1Conversion is sent its analog quantity into the compensation that prime amplifier is finished " preposition zero point of SP+ ".Eight kinds of right compensating signals of different frequency are consistent result of its zeroing integration by the change integration time constant or by two kinds of methods of signal attenuator.
Filtering stage 16 is respectively the active power frequency notch filter of 49.5 ± 0.2Hz and 50.5 ± 0.2Hz by the two-stage trap frequency and the active low-pass filter of one-level 110Hz is formed.Compacting>40db to power frequency.
Main amplifier stage 17 is one 2 system gain amplifiers, the automatic gain control amplifier that is made of anti-phase input proportional amplifier, feedback resistance, interface and eight tunnels analogy converters.Gain (and range of adjustment) is 2 0~2 7Surplus value after prestage " SP+ zero point " compensation and main putting level zero point itself are behind zeroing integrator 18 integrations, equally through A/D; Conversion → storage → D/A 2Conversion → master is put level and is compensated once more.
The Fournier transform device 19 that is concerned with, its physical circuit as shown in Figure 4.The relevant device of the fourier transform of its medium and low frequency real component can preset tetrad up-down counter 5G14516 and 32 single eight channel converter CH4051 and CO43 triggers 28,29,30 by 27, and resistance attenuator 36 is with door 40, or door 41, and follower 31, phase inverter 33, compositions such as switch 42,43.Input end 31 adds a positive direct-current level, and count pulse is added to the 27CP end, and the output terminal 32 will produce a sine wave, and its cycle is by the frequency decision of count pulse.With the compound two-frequency signal after amplifying, what directly be added to sine-wave generator after 33 detections are anti-phase goes into end (being that resistance attenuator is gone into end), the input two-frequency signal that computerizeds control is a low-frequency cycle, and sending out frequency by microcomputer according to synchronizing pulse (current phase benchmark) simultaneously is 32f LCount pulse, obtain the multiplied result of a low-frequency sine and a low-frequency cycle two-frequency signal, by 32 outputs, send into 34 integrations, promptly obtain Re LLow frequency integrator 34 is by the ICL7650 operational amplifier, integrating resistor 46, integrating capacitor 48, integration input switch 44, short-circuit switch of input 457, compositions such as integration erase switch 478 and trigger 30. Integral time 1,2,3,4, class frequency was to long being as the criterion of a low-frequency cycle of the 4th group with lowest frequency; And 5,6,7,8 groups input signal is decayed by 2 letter number in advance one by one, so the integrated value in each big group has consistance.The relevant device of the Fournier transform of low frequency imaginary component is formed by 27,35,28,29,37,38,39,49,50,51,52,53,54,55 etc.35 is opposite with the connection of the connection of resistance attenuator 37 and 32, therefore can export a cosine wave (CW).The two-frequency signal of a low-frequency cycle is sent into the cosine wave (CW) generator after anti-phase through 33, can obtain Im from 35 output terminals L, export by the integrator integration.
The Fournier transform phase utensil of high frequency real component and high frequency imaginary component has and last identical circuit, and what just handle is HFS in the composite signal.And integral time still with the equating of low frequency.
Microprocessor 21.Select eight 80C39 chip microprocessor for use, have the addressing of address function of 4K, its lead-in wire 12-19 is a data bus, is again low eight bit address buses, adopts 2 D4042 as address latch in addition.The address high 3 with the P20-P22 interface on the single-chip microcomputer.All Control Software of instrument all exist among the 2KEPROM of 27C16, and operating ROM is provided by 80C39 itself.Other have 6116 at random reservoir store the field inspection data, its high 3 bit address by the interface P10-P12 of 80C39 provide, low eight bit address then provide by D4042.In addition, also adopt 7 8243 peripheral interface slice, thin pieces, every provides 4 groups 4 totally 16 peripheral interfaces, is deciphered through three-eight decoding C301 by the signal of the P25-P27 of 80C39 and controls.Its output, input port are connected on each required control of instrument, the feedback end, thereby finish getting in touch of microprocessor and instrument each several part.
Microprocessor software.With the control center of combination of hardware, can be provided with on demand, programme, to realize then, relatively to the inspection of various feedback signals as this machine, the issue control signal, coordinate the work of view device each several part, according to various feedback signals, receiver control is finished different measuring abilities.Measured result is carried out analog to digital conversion, data storage, data playback process (the software fundamental block diagram is seen accompanying drawing 5) behind man-machine conversation during for observation and the worker:
1. according to complete machine needs control AD analog to digital conversion and DA1, DA2 analog to digital conversion, finish preamplifier state and mainly put the SP of level and the compensation of instrument zero.
2. for making the master put grade output signal between 800mv-2000mv, microcomputer is adjusted the gain code of preamplifier state and main amplifier stage automatically, realizes automatic gain control.
3. the relevant device of control Fournier transform is finished Re L, Reh, Φ L, Φ h, Rs and SP calculating and detection.
4. realization digital phase shift is eliminated the truth of a matter of phase shift and Rs.
5. deposit each measurement parameter and state parameter (as each group supply voltage, preamplifier state gain, main gain per stage, all numbers of integration put), in order to calling demonstration.
6. the scanning soft-touch control makes soft-touch control have the folk art term function, to satisfy the needs of instrumentation and demonstration.
Gained parameter of the present invention is decided to be:
High frequency real component Reh; Low frequency real component Re L;
High frequency imaginary component Imh; Low frequency imaginary component Im L;
Spontaneous potential SP;
High frequency phase shift phi h=tg -1Imh/Reh
Figure 88105655_IMG2
Imh/Reh;
Low frequency phase shift phi l=tg -1Im L/ Re L Im L/ Re L;
Percent frequency effect;
Real amplitude-frequency rate Rs=((Re L-Reh)/Reh) * 100%.
Liquid-crystal display section 24.This circuit comprises one 3 1/2 LCDs, three seven-segment decoder/LCD driver C306, and one four XOR gate C660, a 82C43 interface, two two-dividers, three phase inverters and resistance, electric capacity is formed.By microcomputer software control, with measurement parameter SP, φ L, φ h, Rs, R L, Rh and ± 12v, ± 6v power supply, and state parameter, preamplifier gain, main amplification gain is measured integration week number, the frequency of observation is delivered to three seven-segment decoder/LCD driver to display screens to group number by interface and is shown.Individual position, ten, hundred figure places, kilobit, symbol and radix point all are to send liquid crystal display to show by interface JS by four XOR gate C660.The liquid crystal display frequency is by resistance, and electric capacity and three phase inverters form that oscillator provides behind four frequency divisions.
Synchronizing signal forwarder 26 is to adopt photoisolator.
25 machines of keyboard adopt touch switching regulator keyboard, by microcomputer software control, realize two retaining functions.Realize the startup of eight class frequencys to measuring on keyboard, Instrument working state, power supply status inspection select to show operations such as desired parameters.
Circuit needs ± 6v the power supply of receiver, chip microprocessor and peripheral chip needs+3v thereof ,-the 2v power supply.Therefore complete machine has four groups of stabilized voltage supplys.

Claims (5)

1, a kind of frequency spectrum stimulated electricity surveying system with double-frequency channels and multiparameters, comprise by electrode and send the transmitter of double frequency electric current and the receiver of reception two-frequency signal to system under test (SUT), the microprocessor part of described receiver is finished following function by interface circuit under the support of software; Carry out spontaneous potential compensation and instrument zero compensation; Realize the automatic gain control of amplifier stage; The conversion of control A/D and D/A converter; The control measurement of correlation; Realize digital phase shift, eliminate the truth of a matter of each parameter of instrument itself; Data processing; It is characterized in that:
1) described transmitter has a double frequency to form circuit, and the continuous square-wave signal that this circuit will differ high and low two kinds of frequencies of certain multiple is combined into the two-frequency signal of forward and reverse constant amplitude, does high-power output through driving circuit and inverter; Before described double frequency forms circuit, a frequency dividing circuit is arranged, convert the fixedly high-frequency signal of a signal source input high and low frequency signal of at least one pair of fixed frequency difference to, export to described double frequency respectively and form circuit;
2) described receiver is provided with the relevant device of analog quantity fourier transform, and the signal that receiver receives is imported the relevant device of described analog quantity fourier transform again after amplifier stage, filtering stage are handled; The relevant device of analog quantity fourier transform comprises an analog sine wave producer or cosine wave (CW) generator, under the control of electronic switch, carry out sine or cosine signal and be exaggerated high frequency in the signal or the multiplying of low frequency signal, realize fourier transform, extract the high frequency real component respectively simultaneously, the high frequency imaginary component, low frequency real component, low frequency imaginary component;
3) described receiver has a synchronizing signal forwarder and transmitter to link;
4) observed parameter is high frequency real component, low frequency real component, high frequency imaginary component, low frequency imaginary component, high frequency phase place, low frequency phase, percent frequency effect, spontaneous potential.
2, induced electrical observing system according to claim 1 is characterized in that, is 9: 1 or 13: 1 through the frequency difference of the high and low frequency signal of frequency dividing circuit conversion.
3, induced electrical observing system according to claim 1 and 2 is characterized in that, the high and low frequency signal of conversion forms many class frequencys under frequency dividing circuit control right.
4, induced electrical observing system according to claim 3 is characterized in that, it is right to form 8 class frequencys by 2 frequencys multiplication relation.
5, induced electrical observing system according to claim 1 and 2, it is characterized in that, the relevant device of fourier transform be by can presetting the tetrad up-down counter, eight tunnels analogy converters, trigger, resistance attenuator, with door or door, follower, phase inverter, electronic switch composition.
CN 88105655 1988-01-15 1988-01-15 Frequency spectrum stimulated electricity surveying system with double-frequency channels and multiparameters Expired CN1015673B (en)

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Publication number Priority date Publication date Assignee Title
CN101581794B (en) * 2009-06-05 2011-04-20 中南大学 GPRS-based remote measuring and controlling system of multi-frequency induced polarization instrument
CN102508302B (en) * 2011-11-01 2013-06-26 中国地质大学(武汉) Underwater main control and data collection system of marine double-frequency induced polarization instrument
CN102520449B (en) * 2011-12-21 2013-08-07 吉林大学 Receiver device of high density electric method device
EP2923226A4 (en) * 2012-11-20 2016-11-02 Univ Rutgers Intelligent spectral induced polarization measurement module
CN103941294B (en) * 2014-05-07 2016-08-17 资阳金贝机电有限公司 High-power spectrum induced polarization detection system
CN104122591B (en) * 2014-06-25 2017-02-15 国家***第一海洋研究所 Double-frequency current signal transmitter in marine electric detection system
CN106646619A (en) * 2016-11-15 2017-05-10 桂林电子科技大学 Novel high-precision mine double-frequency induced polarization receiver
CN108196307B (en) * 2017-12-26 2020-04-24 包金成 Technical scheme for sine wave phase induced polarization

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