Design of sharp FIR filters with prescribed group delay

A method for synthesizing a sharp finite impulse response (FIR) digital filter with prescribed group delay is proposed. In general, the filter length of an FIR filter is inversely proportional to its transition width. Hence, for a sharp linear phase FIR filter the complexity would be very high and the group delay would be very large. Based on a weighted least squares (WLS) algorithm, the frequency response masking approach is extended to the complex domain in order to significantly reduce the required complexity and group delay for synthesizing a sharp FIR filter. The effectiveness of the proposed method is demonstrated by design examples