Frequency selective and matching circuits having improved linearity characteristics of group delay and methods of their realization

Abstract

A possibility of increasing the linearity of phase­frequency characteristics in the broadband matching and filtering using a modification of the classical approximation functions is described. The results of the modified Chebyshev approximation function of the fifth order by the maximum group delay linearity and an analysis of the modified fifth­order Chebyshev function and its comparison with the classical fifth­order Chebyshev function under the same conditions are presented. The implementation of the modified fifth­order Chebyshev filter is shown. It is noted that the modified Chebyshev function of order 5 with respect to the classical Chebyshev function has less unevenness in the band matching (filtration), a smaller value of the approximation error on the integral criterion, a lower level of non­uniformity (PFC) in the band of negotiation (filtration).