Generalized adaptive notch smoothing algorithms

Systems with quasi-periodically varying coefficients (such as certain types of rapidly fading telecommunication channels) can be tracked using the algorithms known as generalized adaptive notch filters (GANFs). We show that estimation accuracy of GANF algorithms, as well as their robustness to the choice of design parameters, can be considerably improved by means of compensating estimation delay effects which occur in the amplitude tracking and frequency tracking loops of GANF filters. The only price paid for the achieved improvements is in terms of a decision delay - the proposed generalized adaptive notch smoothing (GANS) algorithms must be run on delayed input/output data sequences. Since such delay is acceptable in many signal processing and system identification applications, the proposed solution seems to be an attractive alternative to the currently available trackers.