Adaptive filters suitable for real-time spectral analysis

Abstract

Some new cascade structures for adaptive filters are presented. They are especially suitable for real-time applications. Since the new structures are intended to be realized using single chip DSP IC's or single chip custom VLSI circuits the requirements for memory and divisions are minimized. The new structures are based on state-variable biquads that in addition to having good SNR's and low sensitivities (for fixed-point implementations) can also have their resonant frequencies and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</tex> -factors independently tuned. The special cass of using the adaptive filters for tracking sinusoids corrupted by noise and for formant based speech compression are described in detail.