Comparison of adaptive lattice filters to LMS transversal filters for sinusoidal cancellation

The authors compare the performance of the recursive least squares lattice (RLSL) and the normalized step-size stochastic gradient lattice (SGL) algorithms to that of the least mean square (LMS) transversal algorithm for the cancellation of sinusoidal interference. It is found that adaptive lattice filters possess a number of advantages over the LMS transversal filter, making them the preferred adaptive noise cancellation (ANC) filter structure if their increased computational costs can be tolerated. These advantages include faster convergence, notch bandwidths which are independent of the input power, and the generation of less harmonic distortion. The notch bandwidth of each filter structure is related to its respective convergence time constant. Experimental results obtained with the 32-b floating-point lattice development system (LDS) are presented to verify the analytical results