| 摘要 |
A trellis coded modulation (TCM) decoder for a digital television receiver and a TCM decoding method therefor are provided. The TCM decoder includes a branch metric generator calculating a Euclidian distance between a received input data and a reference signal, corresponding to the case of 8-state passing through the comb filter and the case of 4-state not passing through the comb filter, and generating a branch metric value of a path having the smallest value from parallel-transited paths, according to each state and a parallel-transition path select signal wherein each state is based on a trellis state diagram having transition, to share 4-state and 8-state, an addition-comparison selector adding a branch metric value with respect to the parallel-transited path obtained by the branch metric generator to a previous accumulated path metric value, and comparing the added results according to each state to generate the smallest path metric value and a corresponding path select signal, and a trace-back memory tracing-back the trellis using the path select signal and the path metric values of each state, corresponding to both the 4-state and the 8-state, to thereby decode an original signal, in units of a predetermined number of symbols corresponding to interleaving in units of the predetermined number of symbols, to thereby concurrently perform decoding corresponding to an 8-state in using a comb filter for removing the effect of an NTSC signal for the receiver as well as a 4-state.
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