The Research Of Laser Ranging Hardware Circuit Based On AD500

Avalanche Photo diode is a kind of optoelectric detector which has inside gain. Because of its high detection sensitivity, high bandwidth, low noise, it is widely used in many field:weak light signal detection system, laser range finder system and so on. In laser range finder system, it is always used to receive weak light signal which was reflected by target. The principle of phase-shift laser range technology is that high frequency signal modulates on continued emission light intensity. It measures the phase difference from target to get accurate indirect distance, based on mix frequency technology and digital phase-measurement technology.The paper use APD to be research object and design laser signal send and receive, high precision time-counting circuit based on DDS technology and different frequency phase measurement principles. The main methods are:(1) According to the working principle and characteristics of the pulse and phase-shift laser range finder, put forward the overall program based on the phase difference frequency.(2) According to phase-shift principle, High frequency signal laser modulation circuit was designed based on OPA657. It uses AD9834to make main-oscillation signal and local-oscillation signal. It uses OPA657to make up APD pre-amplifier and main amplifier circuit and realizes APD photoelectric current amplification. Auto gain control circuit has been design to stabilize reception signal amplitude based on AD603.(3) Paper deeply research digital phase-identify method, design and debug mixer circuit, active filter circuit, comparator circuit, high-precision time-counting circuit. It uses AD831to realize mixer circuit and down converter. It uses MAX274to form active filter circuit and filtering high frequency signal. It uses MAX913to shape laser pulse reflection signal. It designs high-precision time-counting circuit based on TDC-GP2.(4) Paper analysis the noise resource of photoelectric detection system and measurement error of the different ranging systems.With the development of laser technology and electric technology, laser ranging is developing in high-precision, large range direction. It will be use widely in other fields.