Full tunable digital heterodyne IIR filters
Karl E. Nelson, Michael A. Soderstrand · 1999
A new digital heterodyne filter is proposed that allows a prototype IIR or FIR filter to be shifted through the entire range of digital frequencies from DC to the Nyquist frequency. The unique properties of this new tunable filter are the range of tunability and the fact that all images created by the heterodyne process are cancelled. The proposed heterodyne filter is suitable both as a tunable filter and for use with standard adaptive algorithms to design adaptive digital filters-especially adaptive notch filters.