FRM based FIR filter design - the WLS approach

Frequency-response masking (FRM) technique produces a filter network which comprises several sub-filters with very sparse coefficient values. If the sub-filters are optimized separately, the overall filter network will be suboptimal. In this paper, an unconstrained weighted least squares algorithm for simultaneously optimizing the sub-filters generated by the frequency-response masking technique is presented. Simulation runs show that our proposed technique produces significant reduction in the effective filter length.