A novel technique for design of low distortion FIR filters

A technique based on additive cancellation of opposite phase ripples to obtain a flat frequency response in the pass and stop bands is described. O. Herrmann's formulation (1970) using the Newton-Raphson iterative technique is used to arrive at the design of additively inverse filters which when added together yield a highly flat frequency response filter. Although only low-pass filters were used, the results are applicable to the design of other finite-impulse-response filters