The important problems in IIR adaptive equalizers are stability of the adaptive IIR filters and unimodality in the error surface. In this report we propose a new IIR adaptive equalizer which assures the unimodality and the stability.

This paper presents a fast convergence block adaptive filter in which the filter weights are adjusted based on the conjugate gradient method. The proposed algorithm permits the use of the fast convolution in accordance with the overlapsave method using the FFT, so that it can reduce the computational complexity to O(N log N + N) for N taps FIR filters. Some computer simulations show the faster convergence property of the proposed method than the conventional algorithms such as well-known LMS type techniques.