Study Of Phase Laser Range Finder

The laser rang finder is a precision measuring technology, which is widely used in the military field and the civil field in which high accuracy is needed.In this paper, the major tasks are as follows:The principle of phase laser range finder is discussed. A practical range finder system using laser diode is designed. The circuits including RF, IF as well as digital signal processing circuits used for phase laser range finder are completed.The system is divided into several modules based on the functions. The circuits of every module are designed and debugged. All the programs in Complex Programmable Logic Device and Micro Control Unite are made and debugged.The digital phase detecting circuit is designed based on Complex Programmable Logic Device and Micro-Control Unite; All C programs used in the Micro Control Unite and all Hardware Description Language programs of the Complex Programmable Logic Device are finished. The 3mm precision of the digital phase detector is obtained in the experiment.Dual-Gate MOSFET is used as mixer and the high isolation of the mixer between two input signals is obtained to remove the interference between the low frequency 4MHz and the high frequency 40MHz signals. Experimental results show that the isolation ratio is as high as 27dB.In addition, if make some improvement on it, It can also be used in vehicle rear-end collision avoidance system, building area measuring, field reconnaissance etc.