多带通信号采样的信噪比分析

利用多带通信号欠采样定理和数字变频等技术，可以实现对多个带通信号的同时直接采样及提取处理。当采样率低于信号最高频率的2倍时，采样后信号的信噪比将变差。该文讨论采样后信噪比与模数转换器前的模拟滤波器以及采样率之间的关系，所得结论对数字接收系统设计有指导意义。
关 键 词 带通信号; 均匀采样; 混叠; 噪声带宽

Abstract Using sub-sampling theorem of multiple banpass signals and digital frequency converting techniques, multi-band-pass signals can be directly sampled and processed using no aliasing sampling rate. If sampling rate is lower than the two times of the maximum frequency of the signal, the signal-to-noise ratio will become worse. The relationships of signal-to-noise ratio of sampled signal, analog filter before analog-to-digital converter and sampling rate have been discussed, the results of the discussion have instructiveness for the design of digital receivers.
Key words band-pass signals; uniformly sampling; aliasing; bandwidth of noise