DECODER AND DECODING METHOD

摘要

The deterioration in the error characteristics at transition points in a transmission system is suppressed. A first adder calculates the SM value at a transition from state 00 to state 00 and produces output for a comparator. A second adder calculates the SM value at a transition from state 01 to state 00 and produces output for the comparator. The comparator compares such SM values, selects a maximum-likelihood pass, and sends the results to a set/reset register. An ACS controller detects the unique determination of transition of the state of fixed information (TAB1), outputs a reset signal to the set/reset register storing the SM value in the state to reset the resist value to 0, and outputs a set signal to the set/reset registers storing the SM values other than values corresponding to state 00 of the fixed information (TAB1) to set the resist value to the MAX value.