A New Design Method Of Transitional Polynomial Filters

Abstract

The paper considers a new design method of transitional filters with characteristics intermediate between that of two polynomial filters with arbitrary denominators of the same order. The method assumes that using two given denominator polynomials one tries to realize two ladder RLC filters (which are called here the “phantom” filters). When the L and C elements of these two ladder “phantom” filters are found, the elements of the transitional “phantom” filter are calculated using linear interpolation between the corresponding Ls and Cs found for given denominator polynomials. Then, using these interpolated values one restores the transitional filter transfer function. The approach is illustrated by design of the transitional filters for the Chebyshev and Butterworth polynomial filters.