MAXIMUM LIKELIHOOD SERIES ESTIMATION TYPE EQUALIZER AND MAXIMUM LIKELIHOOD SERIES ESTIMATING METHOD

摘要

PROBLEM TO BE SOLVED: To reduce operation quantity with which branch metric used for maximum likelihood series estimation processing is calculated and also to reduce an error to prevent an error rate characteristic from deteriorating.;SOLUTION: An absolute value detector 201 calculates the absolute value of an error signal I component, an absolute value detector 202 calculates the absolute value of an error signal Q component, and a deciding device 204 compares the absolute value of the error signal I component with the absolute value of the error signal Q component in largeness and smallness. A 2-bit shift circuit 207 shifts the absolute value of the smaller error signal by two bits, a 3-bit shift circuit 208 shifts the absolute value of the smaller error signal by three bits, and an adder 209 adds an output of the circuit 207 and an output of the circuit 208. An adder 210 approximately calculates branch metric by adding an output of the adder 209 and the absolute value of the larger error signal.;COPYRIGHT: (C)2000,JPO