Stability analysis of linear time-varying IIR filter with equalized group delay characteristic

The paper presents a stability analysis of linear time-varying IIR filter with equalized group delay characteristic. A problem of a non-linear phase response of an IIR filter is introduced. An allpass equalizer as a solution is proposed. The changes in the time domain that additional component introduces into the system is pointed out. The linear time-varying difference equation describing the IIR filter is shown. The methodology known from the literature of analysing the stability is presented. Then the algorithm is applied to check the stability of time-varying IIR filter with coefficients improving its time domain characteristic.