Maximum likelihood sequence estimator and maximum likelihood sequence estimating method

摘要

When a maximum likelihood sequence estimator according to the present invention is used as an equalizer or the like for a receiver, a Viterbi algorithm processing portion 331 in the maximum likelihood sequence estimator estimates a transmission symbol Ea_n with a reception signal y_n and an estimated impulse response {Eh_k} corresponding to Viterbi algorithm so as to estimate a maximum likelihood sequence corresponding to a soft decision regardless of a modulating method. A transmission logic code decoder 34 converts a transmission symbol Ea_n into hard decision data Eb_m with a value "1" or "0". An envelop detector 333 that is a transmission line quality evaluating means detects an envelop level p_n of the reception signal y_n. A soft decision value converting portion 334 converts the envelop level p_n received from the envelop detector 333 corresponding to the value "1" or "0" of the hard decision data Ebm received from the transmission logic code decoder 34 so as to obtain soft decision value output data q_m.