Adaptive IIR filter in frequency domain and its application

An adaptive IIR (infinite impulse response) filter in the frequency domain is proposed. This structure may detect every incoming noisy sinusoid in a relatively short period of time. It can also be constructed as a multiple notch filter. Simulation shows that its performance is good enough, even though the desired signal and jammer appear at both the reference and the primary inputs. This result can be applied to improve the performance of a bugging device. The proposed structure saves much more adaptation time than cascaded IIR ALEs (adaptive line enhancers), and also assures the detection of each sinusoid no matter what the initial weight values are