The Development Of Converter/Time Interval Measurement Testing Equipment

Converter and time interval measurement are two important parts of photoelectric radarcomponent. Their performance are directly related to whether system can work normally or not aswell as the accuracy of distance measurement. Therefore, it is necessary to develope a reliable,convenient, excellent and standard test equipment for laser rangefinder and converter.In this paper, a high-performance detection system is developed to test two optical radarparts. The research content mainly includes:(1) The modular design of test system is completed based on PC104.It includes power supplymodule, adjusting circuit module, pulse width detection module,429module, electronic load,A/D, I/O module and signal connecting cable, etc.(2) According to multi-channel different amplitude voltages of the converter, different testcircuits are designed.Combined with the the requirements of measurement error,theconclusion of each voltage fault or not is gived. The test content includes dc voltage,ripplevoltage,115V ac voltage and the frequency of115V,400Hz ac voltage.The test of converter iscompleted by using electronic load. Ripple is expressed by true RMS. The limited bandwidthof the amplifier will cause ripple measurement error because of signal attenuation,so amplifiercircuit aimed at different frequency band of ripple is designed,combined with equivalentcorrection factor to corrected mearsuring result in order to reduce the measuring error.(3) According to the test results of content2, parameters of fault feature are selected. Usingnegative selection algorithm and DS evidence theory, data fusion about two error parametersappear at the same time is made. Finally, the only type of fault judgement is made.(4) The main performance parameters test of three working conditions of laser rangefinder iscompleted based on the FPGA module. The429level conversion circuit is designed and theconversion between time interval and distance is completed.The testing equipment completes performance parameters test of photoelectric radarconverter and laser rangefinder. Dc voltage detection accuracy (no load, full load) is higher than0.5%. Each ripple voltage detection accuracy is above3%(no load, full load). Three-phase115Vac voltage detection accuracy is higher than1%. The measurement accuracy of pulse width andpulse interval is0.005μs.