One-dimensional Pulse Laser Radar Echo Signal Generator Design

One-dimensional laser echo signal generator is an instrument for the performance detection of LADAR. By using this generator we can simulate the receiving echo signals from LADAR in practical work, without doing any complicated outdoor experiment.Based on the analysis of the working principles and the performance parameter of pulsed laser ranging LADAR, this article introduces the design of a laser echo signal generator, which is composed mainly of distance simulation and echo waveform simulation. For distance simulation, this paper introduces the design of a precision delay circuit, used to simulate the pulse travel time when laser radar ranging. This delay circuit relies chiefly on MCU AT89S52 to do data processing and control. The delay accuracy is as high as 107 ps, being able to do examination of the ranging accuracy of LADAR well, by the relative analysis of the voltage caused by the ramp voltage generator from OPA 657 voltage and the transfer voltage from 14 Bit D/A Converter DAC8311, and finally using a high-speed comparator MAX999 to accomplish the output of delay signal. For echo waveform simulation, we mainly use the enlarged resistance thermal noise to simulate the echo signal noise. And finally, superimpose the signal of delay circuit and the noise, generating the final simulation echo signal.We made a prototype and did experiments to validate the design. Through the experimental data analysis, we found that the inaccuracy between the time average of measured delay time and the setting delay time is very small and the stability of the delay time is very high. Through controlling of the noise amplitude and signals, generate different echo signals with various noise ratios which can meet the demand of laboratory performance test.