Atmospheric laser communication becomes one of the hot spots in recent years.Modem technology is an important part of atmospheric laser communication,its reliability directly impact the performance of entire communication system. The article researched chiefly the technolygy of PPM modulation and demodulation in atmospheric channel environment.This article first researched the impact of atmospheric channel environment on the PPM laser signal transmission,including polo shirts atmospheric attenuation effects、turbulence effects and the disturbance of chi hair straighteners optical background noise,then in accordance with the basic principles of PPM, analyzed the PPM's power spectral density、channel capacity、transmission efficiency, at the same time,compared the PPM's hair straighteners performance with OOK and DPIM, Finally established the model of system and chi dazzle simulation and carried out the realization and simulation of PPM modulation and demodulation based on matlab,deduced the bit error rate of PPM modulation under atmospheric channel environment(Lacoste Polo Shirts weak intensity of turbulence),then analyzed the characteristic of error and the best decision threshold.
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