Least-mean square adaptation of the orthogonal block adaptive line enhancer

A new method of adapting the orthogonal block adaptive line enhancer (OBALE) is proposed based on the least-mean square class of algorithms. The method is shown to have a low computational cost with a short adaptive filter length. The latter results from the admission of poles in the filter transfer function which allows the desired sharp, multi-bandpass, frequency response to be achieved with a few coefficients. The adaptive algorithm is derived from the normalised LMS and the recursive LMS algorithms for the orthogonal block filter. Stability monitoring is required to ensure the adaptive poles do not move outside the unit circle but this is shown to be very simple, adding just two extra operations per pole to the algorithm. Simulations are presented to show performance capabilities