Abstract: An adaptive receiver apparatus including a demodulating circuit for demodulating a reception signal, an adaptive equalizer for equalizing a demodulated output to output a demodulated signal, a difference signal upon equalization and a channel impulse response estimate estimated upon equalization, a noise level detector for detecting a noise level based on the difference signal upon equalization, a channel impulse response variation magnitude detector for detecting a variation in the magnitude of the impulse response estimate at a predetermined level, and a coefficient controller for adjusting a coefficient determining a tracking property of an adaptive algorithm of the adaptive equalizer depending on the variation magnitude of the channel impulse response estimate detected by the channel impulse response variation magnitude detector and the noise level detected by the noise level detector.

Abstract: A sequence estimator for estimating a data sequence which is to be transmitted using a Viterbi processor, includes a register for storing, at a predetermined time interval, signals applied to the sequence estimator. A channel impulse response calculator is provided to receive the signals stored in the register which determine an estimated channel impulse response of each of possible transmitted data sequences. The sequence estimator further includes a branch metric calculator which determines a plurality of branch metrics using the receive signal, the possible transmitted data sequence and the estimated channel impulse response.

Abstract: An adaptive equalizer for adaptively equalizing a signal received over a channel on which intersymbol interference occurs. The adaptive equalizer accurately updates the tap coefficients of a transversal filter incorporated therein in a predetermined period of time without fail with no regard to the intersymbol interference on the channel.