GENERALIZED ADAPTIVE NOTCH FILTERS WITH FREQUENCY DEBIASING

Generalized adaptive notch filters are used for identifica-tion/tracking of quasi-periodically varying dynamic systems and can be considered an extension, to the system case, of classical adaptive notch filters. Belonging to the class of causal adaptive filters, the generalized adaptive notch filter-ing algorithms yield biased frequency estimates. We show that this bias can be removed, or at least substantially re-duced. The only price paid for the resulting improvement of the filter’s tracking performance is in terms of a decision de-lay, which must be incorporated in the adaptive loop. Since decision delay is acceptable in many practical applications, the proposed bias/delay trade-off is an attractive alternative to the classical bias/variance compromise. 1