IIR TYPE PERIODIC TIME VARIABLE FILTER AND ITS DESIGN METHOD

摘要

PROBLEM TO BE SOLVED: To effectively calculate a filter coefficient of an IIR type periodic time change filter that realizes an impulse response of plural conventional IIR type time unchange filters approximated by an impulse response represented by a finite time. ;SOLUTION: In a general equation of a time change filter unit 1 of a coder TX, filter coefficients a(k), b(k) are changed as a period of P-times. Thus, the characteristics of the time change filter unit 1 is represented by P-sets of impulse response. In order to obtain the time change filter unit 1 with an equal characteristics as a conventional time change filter unit, the filter coefficients a(k), b(k) are decided to realize the impulse response of the conventional time change filter unit. Then a decoder Rx has an equal function as that of a conventional decoder and the time change filter unit 8 has different filter coefficients c(k), d(k) from those of the conventional time unchange filter.;COPYRIGHT: (C)1997,JPO