Research And Implementation Of Key Technology Of Multi-physical Acquisition Based On Waveform Recorder

With the rapid development of the electronic information industry,the demand for high precision and high speed measurement of a wide range of physical quantities leads to the rapid development of waveform recorder.Waveform recorder is widely used in many fields as a new generation of data acquisition instruments with high precision,high bandwidth and high isolation,which can measure and collect data for a long time.However,subject to foreign technical restrictions and the prohibition of sale of components and other difficulties,the field of waveform recorder development in our country is very difficult,so the development of our country’s waveform recorder technology products is imminent.With high precision,high bandwidth and wide measuring range as the core,this paper studies the hardware design and implementation of multi-physical waveform recorder.The main research contents are as follows:1.Design of general architecture of signal acquisition front-end analog circuit.According to the steps and characteristics of signal acquisition,signal acquisition is mainly divided into four parts: The acquisition and conditioning circuit,anti-aliasing filter circuit,differential amplifier circuit,analog-digital conversion circuit,the acquisition circuit analyzed the characteristics and application scenarios of five different physical quantities,and designed different acquisition and conditioning schemes respectively.The anti-aliasing filter analyzed a variety of filtering circuits,and finally selected Butterworth filter with gentle passband and good rolling performance.Differential amplifying circuit part and analog-to-digital conversion circuit part Two single-end to differential circuits are designed respectively for high speed and low speed circuits.2.Design of key technical schemes for multi-physical quantity signal acquisition.The five kinds of physical quantity acquisition have different emphases and difficulties respectively in the front end of simulation.For high-voltage and high-bandwidth voltage acquisition,a high-precision resistance-capacitance voltage division network is designed,and an adjustable capacitor is used to ensure both voltage division and the stability of the passband amplitude.The unit gain follower is used to ensure isolation and impedance matching in the latter stage.Ac charge amplifier and protection ring are used for acceleration acquisition to improve the stability of charge acquisition.A 16 channel polling sampling scheme is designed for temperature acquisition and an environment temperature compensation scheme is designed.A shunt sampling scheme is designed for current acquisition.Based on the shunt current sampling scheme,an overcurrent protection scheme of reverse shunt Schottky diode combined with average value detection and peak value detection is designed.A shunt calibration scheme was designed for the gain error of strain acquisition,and the strain gain was calibrated from positive and negative gain directions to improve the measurement accuracy.3.Universal and functional circuit design.The hardware circuit measuring board card not only needs the front-end analog sampling circuit,but also needs the back-end data isolation and processing circuit.Since the digital system can not directly process the analog signal,the analog signal needs to be converted to digital signal for processing.The maximum isolated voltage of 1000 V is achieved.A digital storage scheme based on EEPROM is designed to store the calibration gain data of the front-end analog channel.Finally,the detailed tests show that the precision index,bandwidth index and various functions achieve the expected goal under the condition of multiple physical inputs.