Adaptive recursive filtering, and its application in tracking a Doppler frequency shifted sonar signal

Recursive filtering structures model poles and zeros directly, and so enable tracking to be accomplished with a much reduced computational load, although they do introduce stability problems. The present investigation reviews several such recursive processors, and attempts to rank their performance. Important performance measures include convergence rate, noise reduction and computational complexity. Theoretical comparisons of performance are extremely difficult, if not impossible, so simulation is used as the tool for comparison