first signal amplifier 中文意思是什麼
first signal amplifier
解釋
前置信號放大器-
Then we introduce the character of the atmosphere channel, which we emphasized on the atmosphere scatter, absorption and scintillation ' s effect on the laser beam. in chapter, we explain why we used cassegrain telescope to collect the optical signal at first, then the lightsource, detector, front amplifier used in optical communication has been compared to that of fiber communication, the noise including shot noise, thermal noise and background light noise has been explained here for analysis the snr and ber in the next section
在第三章介紹無線光接入系統的光收發單元，採用多孔徑卡塞格倫式的收發天線對消除減小大氣湍流影響有較大作用，針對大氣通道的特點無線光系統收發單元在光源、光探測器、前置放大電路上存在許多有別于光纖通信的技術，同時還闡述了光接收機包括背景噪聲的噪聲機制和接收靈敏度、誤碼率等指標，最後給出了一個整個傳送鏈路的功率預算。 -
Based the research on the laser beam drift feedback control technique, analysing the beam drift and its frequency components, a laser beam directional stability method is studied in the thesis in detail, with its measurement and control circuit system that combines the laser beam intensity modulation and the beam drift feedback control technique. in this method, at first the laser beam intensity is modulated with the acoustooptic modulator, then the lock - in amplifier is applied to detect and demodulate the modulating signal, at last a feedback control signal is generated by the dsp control circuit at last, including : 1
本文在原有的激光光束漂移量反饋控制準直技術的基礎上，對光束漂移量信號的數據和頻譜進行了分析，重點研究了一種集聲光調制光強與光束漂移量反饋控制準直技術於一體的激光光束方向穩定方法及其測控電路系統，該方法通過聲光調制實現光強調制，接著通過鎖相放大電路檢測並解調調制信號，然後通過dsp控制電路進一步對光束的漂移量進行反饋控制。
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