Approximation Problem for Resonator Ladder Filters

Sufficient conditions have previously been obtained in order that an insertion-loss function be realizable in the form of a resonator ladder band-pass filter. In this paper a modified elliptic function is derived which satisfies the realizability criteria and, furthermore, will satisfy any set of standard filter specifications in terms of ripple, selectivity, etc. A computer program has been written to realize the resulting filter from these specifications and a brief summary of the computer results is included.