| Laser ranging device is one of the key technologies in the target detection area, andbecause of its high accuracy, it is getting more and more important in fields such asaerospace, military science, economic construction and medical care.In this thesis, the related theory and technology are summarized, and the delaysimulator and receiving circuit for laser signals are discussed in detail. Then the delaycircuit, peak holding circuit and timing discriminator circuit are designed based onthese theories. Experimental consequences show that, the performance indexes of thedesigned units reach the expected level, and the design can be used in the project.Firstly, the basics and component parts of laser ranging finder are introduced, andduring the introduction, the tasks of the article are listed. At the same time, the designscheme for every unit is brought out.Secondly, the delay simulator for pulse signal is elucidated and designed, usingFPGA (field programmable gate array) and digital programmable delay generatorAD9501. At last, the simulator can create a synthetic distance, of which the precisionis less than1cm and the measuring range is up to50Km.Then, the peak holding circuit for fast narrow pulse is designed to get the peakamplitude, with operational transconductance amplifier and buffer. Simulationconsequences show that, using gain of+2closed-loop buffer to expand the region ofpeak amplitude, transconductance peak holding circuit can curtail response time andexpand working region. When the rising time of input signal is more than6ns, thecircuit can work normally even if peak amplitude is up to2.5V, and its response time isless than2ns.At last, after the comparison of three design methods to realize timing pinpoint, theconstant fraction timing discriminator circuit is chose to get the accurate arriving timeof the echo signal. This unit is carried out to get ready for the flying time measurement, using a delay circuit, a decay circuit and a high speed comparator. |
PDF Full Text Request