CN201885679U

CN201885679U - Linear displacement sensor demodulation conditioning circuit

Info

Publication number: CN201885679U
Application number: CN2010206049447U
Authority: CN
Inventors: 贾惠霞; 郭强
Original assignee: XI'AN BEIFANG JIERUI OPTOELECTRONICS TECHNOLOGY Co Ltd
Current assignee: XI'AN BEIFANG JIERUI OPTOELECTRONICS TECHNOLOGY Co Ltd
Priority date: 2010-11-18
Filing date: 2010-11-18
Publication date: 2011-06-29
Anticipated expiration: 2020-11-18

Abstract

The utility model discloses a linear displacement sensor demodulation conditioning circuit. The linear displacement sensor demodulation conditioning circuit is characterized in that a digital chip of the circuit is electrically connected with a D/A (digital-to-analog) converter, the D/A converter is electrically connected with a filter, sine waves with 100kHz frequency are generated, the filter is electrically connected with an amplifier, the amplifier, a power amplifier and a PID (proportion-integration-differentiation) controller are electrically connected with each other, the power amplifier, the PID controller, a linear displacement sensor and a multiplier are electrically connected with each other, and the multiplier is electrically connected with a low pass filter. The circuit consists of an excitation signal generating circuit and a linear displacement amplitude-modulated signal demodulating circuit, the excitation signal generating circuit can output sine wave signals with 100kHZ frequency and distortion smaller than 1%, and the integral delay of the demodulating circuit is smaller than 100ns.

Description

A kind of linear movement pick-up demodulation modulate circuit

Technical field

The utility model relates to a kind of linear movement pick-up modulate circuit, is used to cooperate the linear movement pick-up of differential transformers pattern, can shake the micron-sized displacement of the lines that causes by recognition object.

Background technology

At present, the principal mode of linear movement pick-up is grating chi and differential transformers; The measuring accuracy of grating chi is very high, but complex structure, the environmental requirement height, volume is big, costs an arm and a leg.And the linear movement pick-up that differential transformers constitutes, except precision poor slightly, in volume, reliability with very big advantage is arranged in price.Commercial small-sized linear movement pick-up need cooperate modulate circuit separately to use at present, and the measuring accuracy maximum can only reach 0.01 millimeter, can't satisfy micron-sized measurement requirement.

Summary of the invention

The utility model provides a kind of differential transformers modulate circuit, theoretical principle according to differential transformers, adopt the method that improves exciting signal frequency, reduced the harmonic distortion of sensor, utilize the multiplier demodulation principle, strengthen the effect of differential transformers output signal filtering, finally made the linear movement pick-up measuring accuracy reach micron level most.

The technical scheme that the utility model technical solution problem is adopted is:

Digit chip and D/A converter are electrically connected, D/A converter and wave filter are electrically connected, producing frequency is the 100KHz sine wave, wave filter and amplifier are electrically connected, amplifier and power amplification and PID control are electrically connected, power amplification and PID control, linear movement pick-up and multiplier are electrically connected, and multiplier and low-pass filter are electrically connected.

Digit chip and D/A converter are electrically connected, and producing frequency is the near sinusoidal ripple of 100KHz.

D/A converter and wave filter are electrically connected, and producing frequency is the 100KHz sine wave.

Adopt digit chip control D/A converter to produce the 100KHz sinusoidal signal by look-up table, obtain the 100KHz sinusoidal signal of low distortion through the further filtering high fdrequency component of wave filter, pass through amplifier, power amplifier and PID control circuit structure are set up the amplitude feedback control loop, stablize 100KHz sinusoidal signal amplitude, this sinusoidal signal is used to encourage the linear movement pick-up of differential transformers formula, and the output signal that offers multiplier and linear movement pick-up multiplies each other, the output signal of multiplier is exported to measuring equipment after low-pass filtering, as oscillograph, the amplitude of final signal will be represented the displacement of the lines of object.Owing to use digital device to produce initialize signal, be not vulnerable to the influence of environment temperature, this scheme can be applicable to wide temperature range, as-40 ℃ to+70 ℃.And frequency of utilization is the excitation of the sinusoidal signal of 100KHz as linear movement pick-up, far above normally used 20KHz frequency, and employing multiplier demodulation principle has improved the frequency difference between pumping signal and the output signal, the amplitude versus frequency characte parameter designing that helps low-pass filter more makes the displacement measurement precision reach micron order.

Description of drawings

Fig. 1 is a schematic block circuit diagram of the present utility model

Below in conjunction with accompanying drawing the utility model is further specified.

Embodiment

With reference to shown in Figure 1, digit chip 1 can adopt single-chip microcomputer, DSP or fpga chip, digit chip 1 and D/A converter 2 are electrically connected, D/A converter 2 converts the digital signal of digit chip 1 output to simulating signal output, when digit chip 1 was provided with the digital signal that adopts the look-up table output rule by chip, D/A converter 2 can produce the near sinusoidal ripple that frequency is 100KHz; D/A converter 2 and wave filter 3 are electrically connected, wave filter 3 is with the high fdrequency component in the filtering 100KHz near sinusoidal ripple, the output signal of wave filter 3 is the low distortion sine wave signal of frequency 100KHz, the low distortion sine wave exciting signal of output 100KHz after amplifier 4 and power amplification 5, pumping signal is stablized the amplitude of self by the backfeed loop of PID control 6, and linear movement pick-up 7 is driven; The output of linear movement pick-up 7 and multiplier 8 are electrically connected, multiplier 8 multiplies each other the output modulation signal of linear movement pick-up 7 and the pumping signal of power amplification 5 outputs, obtain multiplier 8 restituted signals and output to low-pass filter 9, the high fdrequency component in the low pass filter filters out restituted signal obtains the low frequency amplitude signal of final representative displacement body.

Claims

1. linear movement pick-up demodulation modulate circuit, comprise digit chip, D/A converter, wave filter, amplifier, power amplification, PID control, multiplier and low-pass filter, it is characterized in that, digit chip and D/A converter are electrically connected, D/A converter and wave filter are electrically connected, producing frequency is the 100KHz sine wave, wave filter and amplifier are electrically connected, amplifier and power amplification and PID control are electrically connected, power amplification and PID control, linear movement pick-up and multiplier are electrically connected, and multiplier and low-pass filter are electrically connected.

2. a kind of linear movement pick-up demodulation modulate circuit according to claim 1 is characterized in that, digit chip and D/A converter are electrically connected, and producing frequency is the near sinusoidal ripple of 100KHz.

3. a kind of linear movement pick-up demodulation modulate circuit according to claim 1 is characterized in that, D/A converter and wave filter are electrically connected, and producing frequency is the 100KHz sine wave.