Narrowband interference cancellation through the use of digital recursive notch filters

摘要: A digital notch filter apparatus for removing narrowband interference signals from a wideband communication signal. The includes recursive passband acquisition filter, an mode center frequency control circuit, tracking circuit and detection circuit. has narrower bandwidth than the filter. Both filters are gang tuned so that frequencies of their passbands adjusted in unison. During mode, is used to adjust over covered by canceler. When detects signal within insure remain locked onto Upon signal, portion which passed through narrow subtracted remove no detected, permitted pass output without attenuation.