narrow band receiver 中文意思是什麼
narrow band receiver
解釋
窄帶接收機-
A novel communication receiver which uses lapped transform ( lt ) incorporating modified median filter ( mmf ) algorithm is designed for narrow - band interference excision. the lt domain mmf algorithm takes full advantages of the direct sequence spread spectrum signal, as well as the characteristics of lt, performing the transform domain filtering twice. the first filtering locates the position of interference and mitigates most of them. the second filtering is performed in a small neighborhood of the located interference. so lt domain mmf algorithm can completely mitigate the interference without distorting the desired signal. simulation results demonstrate the improved ber performance and increased robustness of our receiver
本文採用改進的重疊變換域中值濾波演算法進行變換域抗干擾處理.該演算法既考慮到直接序列擴頻信號的特點，同時又利用重疊變換的特性對變換域系數進行了二次濾波.該演算法節省處理時間，並且不需要有關干擾的先驗知識，系統性能不會隨干擾頻率變化而變化，因而是一種很穩健的處理方法 -
Digital down - converter ( ddc ) is one of the key technologies used by sdr receiver. the ddc module is a data processing part, following the ad sampler. the main function of ddc is extracting narrow - band data from broad - band data which is digitalized by ad sampler, down - converting these data to base - band, and decreasing data rate as well
Ddc數字下變頻器技術作為軟體無線電中的核心技術，是緊跟在ad采樣后的一個處理模塊，他的主要功能是從輸入的寬帶高速數字信號中提取所需的窄帶信號，將其下變頻為數字零中頻，並降低數據的速率。 -
The receiver works on active mode and passive mode in different time. in active mode, the receiver is narrow - band and high sensitive, and if phase - lock technology is used to stabilize receiving frequency. and in passive mode, the receiver is an all - power millimeter wave radiometer with periodic calibration to improve measure precision
此接收機採用分時工作體制，在主動工作方式時為窄帶的高靈敏度毫米波接收機，接收機中採用中頻鎖相技術，簡化了毫米波鎖相帶來的困難；在被動工作方式時為全功率型的毫米波輻射計，這種輻射計在每次測量后都採用兩個標準源對輻射計定標，實現周期定標，消除因系統增益波動和有效本機噪聲波動帶來的測量誤差，提高測量測量精度。
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