CN204989320U - Accurate resistance measurement appearance that exchanges - Google Patents
Accurate resistance measurement appearance that exchanges Download PDFInfo
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- CN204989320U CN204989320U CN201520454551.5U CN201520454551U CN204989320U CN 204989320 U CN204989320 U CN 204989320U CN 201520454551 U CN201520454551 U CN 201520454551U CN 204989320 U CN204989320 U CN 204989320U
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Abstract
The utility model relates to an accurate resistance measurement appearance that exchanges, which comprises a microprocessor, sine wave oscillator, the frequency divider, the phase control ware, a sine wave generator, the 2nd sine wave generator, the wave filter, signal selector and phase discriminator, sine wave oscillator is connected to the input of frequency divider, a sine wave generator and the 2nd sine wave generator are connected respectively to the output of frequency divider, the sinusoidal wave test signal source as the phase discriminator that a sine wave generator produced, sine wave signal that the 2nd sine wave generator produced is as the reference signal source of phase discriminator, the vectorial resultant voltage of standard resistance and measured piece is recorded through the phase discriminator, erupt simultaneously and give microprocessor, obtain the resistance value of measured piece. The utility model discloses a phase discriminator measuring technique replaces classic bridge measurement technique, has eliminated the difference between common mode current output and the detection converter scale coefficient, and it is more accurate to measure, and simple structure is with low costs.
Description
Technical field
The utility model relates to a kind of accurate AC resistance measuring instrument.
Background technology
China once developed AC resistance in the seventies, and because the quality of nickel-base alloy is at that time immature, and service condition is not yet formed at that time, therefore did not draw and produce on a large scale.In the eighties and electromagnetism place of China National Measuring Science Research Inst. research AC resistance, in view of its 1 ~ 100,000 ohm the time constant not yet ripe of basic condition is then 1 × 10-8, frequency is 50 weeks, Major Difficulties is resistance material (resistivity is about 0.48), the correcting device precision of alternating-current parameter is not high enough, and alternating current-direct current transforms error low resistance at 50ppm.
Development instrument and meter industry, exploitation has independent intellectual property right, the instrument industry Hua Shi National Development and Reform Committee of original technology, commerce commission, information industry, State Bureau of Technical Supervision list one of emphasis subject " 12 " planned in, developing goal, direction have been pointed out in development for instrument and meter industry, make instrument product can adapt to the demand of all trades and professions all sidedly, progressively forming complete instrument and meter industry system, reach international similar-type products level, is national economy service.
Along with China joined WTO tissue, many technical requirements relatively not high, labour-intensive, that environmental protection cost is high industry are transferred to domestic, comprising electronic devices and components manufacturing, as capacitor, inductor, resistor manufacturer in large quantities.These manufacturers need a large amount of High-precision standard AC resistance measuring instruments especially multi-parameter comprehensive measuring instrument.According to investigation, the measuring instrument used on a production line, accuracy requirement is generally 0.1%, test frequency only needs some fixing frequencies (as: 100Hz, 1kHz, 100kHz), test voltage is at 10mV ~ 1V, and measuring speed requires very fast (more than 2 times/second), and large-scale image LCD shows, the operation requirements of instrument is more convenient, and band sorting interface is so that automatic test machine uses.
High-precision standard AC resistance measuring instrument is a kind of automatic AC impedance measuring Instrument, can be applicable to metrological service, components and parts manufacturer uses, on this basis, and the multi-parameter comprehensive measuring instrument such as resistance, inductance, electric capacity of development measurement and sorting passive device.Domesticly at present not yet form unified AC resistance measuring method, as lacked theoretical foundation to the uncertainty analysis of product, the still defectiveness of measurement especially at different frequencies.
Classic bridge measurement technology is a kind of metering system of single bridges, its numerical value general measure be middle resistance value, to measuring low resistance, just clearly, the resistance value that can accurately not obtain wanting, error is large and cost is high for the error that its metering system produces.
Utility model content
The purpose of this utility model is to provide a kind of accurate AC resistance measuring instrument, described measuring instrument records the Vector modulation voltage of measuring resistance and measured piece by phase detector, and send to microprocessor, the resistance value of measured piece is calculated by microprocessor, instead of classic bridge measurement technology, eliminate the difference between common mode current output with detection converter calibration factor, measure more accurate, structure is simple, and cost is low.In order to solve the problem that the accuracy of traditional electric bridge measuring technique is low, cost is high, error is large.
For achieving the above object, scheme of the present utility model is: a kind of accurate AC resistance measuring instrument, and described accurate AC resistance measuring instrument comprises microprocessor, sine-wave oscillator, frequency divider, phase controller, primary sinusoid generator, the second sine-wave generator, wave filter, signal selector and phase detector;
The signal output part of described sine-wave oscillator is connected with the signal input part of frequency divider, the test signal output terminal of described frequency divider connects primary sinusoid generator by phase controller, and the reference signal output terminal of described frequency divider connects the second sine-wave generator by described phase controller; Described microprocessor-based control output terminal connects frequency divider, and for entering horizontal phasing control to the signal of frequency divider reference signal output terminal, the signal output part of described second sine-wave generator connects the reference signal input end of phase detector; The signal output part of described primary sinusoid generator connects wave filter, the signal input part of the signal output part connection signal selector switch of described wave filter, and the signal output part of described signal selector connects the test signal input end of phase detector; The data output end of described phase detector connects the input end of microprocessor.
According to accurate AC resistance measuring instrument described in the utility model, described accurate AC resistance measuring instrument comprises power amplifier and operational amplifier, after described power amplifier operational amplifier serial connection, is connected between described wave filter and signal selector.
According to accurate AC resistance measuring instrument described in the utility model, the reference signal input end of described phase detector inputs the reference signal of four kinds of phase places.
According to accurate AC resistance measuring instrument described in the utility model, described primary sinusoid generator and the second sine-wave generator comprise sinusoidal ROM and show and D/A converter.
According to accurate AC resistance measuring instrument described in the utility model, described accurate AC resistance measuring instrument comprises display, and described display is connected to the signal output part of microprocessor by Peripheral Interface adapter.
According to accurate AC resistance measuring instrument described in the utility model, described accurate AC resistance measuring instrument comprises keyboard, and described keyboard is connected with the signal input part of microprocessor, for sending measuring-signal by Peripheral Interface adapter.
According to accurate AC resistance measuring instrument described in the utility model, described accurate AC resistance measuring instrument inside arranges one group for realizing the calibration resistor of automatic calibration function.
The beneficial effect that the utility model reaches:
(1) accurate AC resistance measuring instrument of the present utility model adopts microprocessor, the Vector modulation voltage of measuring resistance 90 degree and anti-phase 90 degree voltages orthogonal with measured piece two ends can be recorded by phase detector and analog to digital converter fast, do not adopt classic electrical bridge principle, eliminate common-mode current value and export difference between detection converter calibration factor, measuring accuracy is high.
(2) the utility model adopts quick phase detector technology, the test signal of phase detector input end and reference signal are from same high-frequency signal source, phase place between four kinds of reference signals accurately differs 90 degree, the frequency of reference signal and test signal is just the same, therefore high-precision analog phase shifter or waveform shaping circuit (being whittled into square wave) is not needed, test process is easier, and tester structure is more simple, saves cost.
Accompanying drawing explanation
Fig. 1 is accurate AC resistance measuring instrument circuit theory diagrams of the present utility model;
Fig. 2 is the measuring principle figure of the utility model phase detector;
Fig. 3 is the schematic diagram of the utility model sine-wave generator;
Fig. 4 is self-calibration technique schematic diagram of the present utility model.
Embodiment
Below in conjunction with accompanying drawing and specific embodiment, the utility model is described in further detail.
As shown in Figure 1, accurate AC resistance measuring instrument described in the utility model comprises microprocessor, sine-wave oscillator, frequency divider, phase controller, primary sinusoid generator, the second sine-wave generator, wave filter, power amplifier, operational amplifier, signal selector and phase detector.Described sine-wave oscillator is for generation of the test signal of sine wave, the signal output part of described sine-wave oscillator is connected with the signal input part of frequency divider, the test signal output terminal of described frequency divider connects primary sinusoid generator by phase controller, the reference signal output terminal of described frequency divider connects the second sine-wave generator by described phase controller, the frequency of described reference signal and the frequency of test signal just the same.
Described microprocessor-based control output terminal connects frequency divider, for entering horizontal phasing control to the signal of frequency divider reference signal output terminal, the signal output part of described second sine-wave generator connects the reference signal input end of phase detector, signal after phase place adjustment, through the second sine-wave generator, exports the derived reference signal of quasi-sine-wave signal as phase detector.
The signal output part of described primary sinusoid generator connects wave filter, the sine wave signal of the signal output part output of described wave filter is after power amplifier and operational amplifier, the signal input part of connection signal selector switch, the signal output part of described signal selector connects the test signal input end of phase detector, and the sine wave signal smoothly exported afterwards by described filter filtering is as the testing source of phase detector.
The data output end of described phase detector connects the input end of microprocessor by Peripheral Interface adapter, the voltage signal that microprocessor exports according to phase detector, determine the resistance of to be measured, the data output end of microprocessor also connects display, and microprocessor is shown test results by display.
When accurate AC resistance of the present utility model carries out work, produce sinusoidal test signal by sine-wave oscillator, and be input in frequency divider, by frequency divider, scaling down processing is carried out to described sinusoidal test signal; Sinusoidal test signal through frequency division is divided into two-way to export, and wherein the first via directly outputs to primary sinusoid generator, and the second tunnel, after carrying out phase shift under microprocessor-based control, sends to the second sine-wave generator; After first via fractional frequency signal enters primary sinusoid generator, as the address of the sine wave table stored in storer, then according to sine wave table address, take out the quasi-sine-wave of flash memory in storer, and after filtering after device smoothing processing as the testing source of frequency discriminator; After second road fractional frequency signal enters the second sine-wave generator, change the address of sine wave table, realize, to the quasi-sine-wave phase shift exported, obtaining the quasi-sine-wave of four kinds of phase places, as the derived reference signal of phase detector, the frequency of described reference signal and the frequency of test signal just the same; Described phase detector, according to the test signal of input and reference signal, obtains the Vector modulation voltage of measuring resistance and measured piece, and outputs to microprocessor, the voltage signal that microprocessor exports according to phase detector, obtain the resistance of to be measured.
As shown in Figure 2, what k represented is amplifier,
for the voltage vector at measured resistance Zx two ends,
for the voltage vector at measuring resistance Rs two ends,
for flowing through the electric current of measured resistance and measuring resistance.
As long as record
the value of tested Zx can be obtained.The voltage signal at what the reference signal input end of described phase detector obtained is measuring resistance Rs two ends, the voltage signal at what the test signal input end of described phase detector obtained is measured piece Zx two ends, described phase detector records the Vector modulation voltage of measuring resistance Rs 90 degree and anti-phase 90 degree voltages orthogonal with measured piece Zx two ends, and send to microprocessor by Peripheral Interface adapter, by the resistance value obtaining measured piece after microprocessor processes, then the resistance value recorded is shown by display.
Phase detector of the present utility model adopts the reference signal of four kinds of phase places, and namely phase place is respectively 0 degree, 90 degree, and the sine wave signal of 180 degree and 270 degree, the effect of phase detector is just used to discriminating and distinguishes 0 degree, 90 degree, 180 degree, 270 degree of these four phase places.Four kinds of phase reference signals that the utility model phase detector adopts are separated with accurate 90 °, therefore accurate AC resistance measuring instrument does not need high-precision analog phase shifter or wave rectification circuit, and correct phase relation ensures by from the test signal of same high-frequency signal source and reference signal.The utility model replaces classic bridge measurement technology by phase detector measuring technique, eliminates the difference between common mode current output with detection converter calibration factor.
As shown in Figure 3, the drive singal of the 64 times of frequency test signals selected is provided by digital circuit, frequency divider (binary counter) countdown from 64f, export 32f, 16f, 8f, 4,2f and f six kinds of signals are as the address of sinusoidal wave ROM, take out 64 grades of contents of the quasi-sine-wave (staircase waveform of near sinusoidal ripple) of flash memory in ROM, control D/A converter again and export quasi-sine-wave, the sine wave after filtering after device smoothing processing is exactly testing source.
If the sinusoidal wave initial phase that Fig. 3 produces is 0 degree, by microprocessor, suitably phase shift is carried out to these two signal wires of 2f and f that frequency divider exports, namely choosing of sine table ROM initial address is changed, just can to the quasi-sine-wave phase shift exported, thus obtain four kinds (0 degree, 90 degree, 180 degree, 270 degree) quasi-sine-wave (frequency is constant) of phase place carrys out as phase detector derived reference signal.
Accurate AC resistance measuring instrument of the present utility model have employed Automatic Calibration Technique, and resistance measuring instrument does not in the past have self checking function, each start needs the different resistance of external a lot of resistance, calibrates instrument, and the workload of operating personnel greatly and more loaded down with trivial details.
As shown in Figure 4, accurate AC resistance measuring instrument inside is provided with 4 calibration resistors, and it is known that internal standard impedance (is generally 1KHz) under calibration frequency, and the impedance of each internal standard resistance is stored in RAM.Accurate AC resistance measuring instrument of the present utility model adopts " automatic calibration " technology to revise the impedance of internal standard resistance, before the use, first an external perimysium reference resistance is set, an existing resistance measuring instrument GR1689 is adopted to calibrate external perimysium reference resistance, with the precision of confirmed standard resistance, then external perimysium reference resistance is utilized to calibrate its internal resistance, by the deposit data of having calibrated in the internal storage of instrument, the accuracy value of the measuring resistance of outside is just equivalent to be stored in instrument internal, the primary calibration to inner 4 the measuring resistance resistances of the accurate AC resistance measuring instrument of the utility model is realized by external perimysium reference resistance, each start later, instrument just need not external measuring resistance be calibrated, but by the accuracy value of storage inside, self calibration is carried out to 4 resistance of instrument internal, realize the automatic calibration function of himself.
Accurate AC resistance measuring instrument of the present utility model adopts microprocessor, by phase detector and analog to digital converter can record the Vector modulation voltage at measuring resistance and measured piece two ends fast, do not adopt classic electrical bridge principle, eliminate common-mode current value and export difference between detection converter calibration factor, simultaneously, by adopting quick phase detector technology, the test signal of phase detector input end and reference signal are from same high-frequency signal source, phase place between four kinds of reference signals accurately differs 90 degree, the frequency of reference signal and test signal is just the same, therefore high-precision analog phase shifter or waveform shaping circuit (being whittled into square wave) is not needed, test process is easier, tester structure is simpler, save cost.
Claims (7)
1. an accurate AC resistance measuring instrument, is characterized in that: described accurate AC resistance measuring instrument comprises microprocessor, sine-wave oscillator, frequency divider, phase controller, primary sinusoid generator, the second sine-wave generator, wave filter, signal selector and phase detector;
The signal output part of described sine-wave oscillator is connected with the signal input part of frequency divider, the test signal output terminal of described frequency divider connects primary sinusoid generator by phase controller, and the reference signal output terminal of described frequency divider connects the second sine-wave generator by described phase controller; Described microprocessor-based control output terminal connects frequency divider, and for entering horizontal phasing control to the signal of frequency divider reference signal output terminal, the signal output part of described second sine-wave generator connects the reference signal input end of phase detector; The signal output part of described primary sinusoid generator connects wave filter, the signal input part of the signal output part connection signal selector switch of described wave filter, and the signal output part of described signal selector connects the test signal input end of phase detector; The data output end of described phase detector connects the input end of microprocessor.
2. accurate AC resistance measuring instrument according to claim 1, it is characterized in that, described accurate AC resistance measuring instrument comprises power amplifier and operational amplifier, after described power amplifier operational amplifier serial connection, is connected between described wave filter and signal selector.
3. accurate AC resistance measuring instrument according to claim 1, is characterized in that, the reference signal input end of described phase detector inputs the reference signal of four kinds of phase places.
4. accurate AC resistance measuring instrument according to claim 1, is characterized in that, described primary sinusoid generator and the second sine-wave generator comprise sinusoidal ROM and show and D/A converter.
5. accurate AC resistance measuring instrument according to claim 1, is characterized in that, described accurate AC resistance measuring instrument comprises display, and described display is connected to the signal output part of microprocessor by Peripheral Interface adapter.
6. accurate AC resistance measuring instrument according to claim 1, is characterized in that, described accurate AC resistance measuring instrument comprises keyboard, and described keyboard is connected with the signal input part of microprocessor, for sending measuring-signal by Peripheral Interface adapter.
7. accurate AC resistance measuring instrument according to claim 1, is characterized in that, described accurate AC resistance measuring instrument inside arranges one group for realizing the calibration resistor of automatic calibration function.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520454551.5U CN204989320U (en) | 2015-06-29 | 2015-06-29 | Accurate resistance measurement appearance that exchanges |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201520454551.5U CN204989320U (en) | 2015-06-29 | 2015-06-29 | Accurate resistance measurement appearance that exchanges |
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| CN204989320U true CN204989320U (en) | 2016-01-20 |
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