Selective, constant delay wave digital filters
G. Denton, Herbert J. Carlin · International Journal of Circuit Theory and Applications · 1979
Abstract A wave digital filter design method is discussed which produces good selectivity and flat delay characteristics. The filter is designed in the microwave domain with monotonic stopband response using Carlin and Wu's technique for minimum‐phase linear phase commensurate line transducers, then realized in the digital domain with Fettweis relations. A comparison is made of frequency response sensitivity to multiplier coefficient truncation between this wave filter and some FIR's, all with approximately the same number of multipliers. The cascade realizations of the FIR's show considerable passband amplitude response deterioration due to coefficient truncation, whereas the direct realizations for the FIR's show significant deterioration of stopband amplitude response owing to coefficient truncation. Coefficient truncation for the wave digital filter caused relatively small deterioration of both passband and stopband amplitude responses as well as small distortion of the flat delay characteristic in the passband.