Linear phased filter for reducing ripple in group delay

摘要

A first filter the group delay of which in the pass band contains a ripple is connected to a second filter so as to cancel the ripple. The second filter has a pass band at least within the pass band of the first filter. The gain of the second filter is reduced gradually from the frequency of the minimum attenuation into the lower and higher frequency regions and the group delay thereof is reduced gradually from the frequency of the minimum attenuation into the lower and higher frequency regions.