Pulse or digital communications – Receivers – Interference or noise reduction
Patent
1995-06-02
1997-08-19
Chin, Stephen
Pulse or digital communications
Receivers
Interference or noise reduction
375350, 329349, H04B 110
Patent
active
056595832
ABSTRACT:
Techniques in a QAM digital communication system for canceling one or more interference tones in an incoming signal to produce an output signal by generating an estimate of the interference tone during the current processing interval, subtracting the estimate to produce the output signal, and modifying, if necessary, adaptive circuitry for use during the next processing interval. Techniques which apply either at passband or at baseband, that is, before or after mixing the incoming signal with the recovered carrier, are disclosed. The adaptive circuitry includes a single weighting parameter or an adaptive filer. Passband techniques utilize rerotation of baseband signals to appropriately align the spectra of the processed signals.
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Chin Stephen
Hitachi America Ltd.
Kim Kevin
Michaelson Peter L.
Peoples John T.
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