High-precision measurement technology of laser pulse flight time based on TDC-GP21

With advanced minute time interval measurement chip TDC-GP21 which is an application specific integrated circuit(ASIC), a high precision pulse laser ranging finder system was designed and achieved in this paper. Meanwhile, the workflow chart and external circuits were discussed. Optical signal receiving and amplifying circuit were also studied; the basic theory of transimpendance amplifier was also discussed and analyzed in detail. Further more, the method of triangle wave fixed propagation delay was put forward for time distinction which could greatly reduce the requirements of echo signal amplitude. That was pretty important to laser ranger finder. The results of the experiment prove that a centimeter accuracy system can be achieved with the above technology. At last, the pulse laser ranging system with small size which is easy to acquire has really simple structure and can achieve high degree accuracy which meets high precision laser distance measurement requirement with low power consumption and cost.