In Chapter 3, the concept of matched
filtering of baseband data signals for optimizing the signal to noise ratio at the
output of a data receiver was discussed. Exactly the same approach is applicable to
bandpass modulation detection and in fact the bandpass case reverts to the baseband case
for ASK if coherent detection is used to 'demodulate' the ASK
signal and hence recover the source baseband data stream. A matched filter pair such as the root raised cosine filters can thus be used to shape the source and received baseband data symbols in ASK, and in fact this is a very common approach to achieving matched filter detection in most bandpass data modems. |
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