| 摘要 |
A Viterbi decoder for decoding a convolution coded reception signal. The Viterbi decoding uses an algorithm for efficiently executing the maximum likelihood decoding using a convolution code by selecting a path locating at the minimum distance from a reception series between two paths which are joined. Since it is necessary to store a state metric of each state, after the state metric of the surviving path was calculated by ACS calculation, it is considered to normalize metrics. However, this results in a large circuit scale and a low processing speed. Therefore, in this invention, a maximum likelihood value of a present state metric is detected from a maximum likelihood branch metric pair before the ACS calculation and the preceding maximum likelihood state metric pair and metrics are normalized by using the maximum likelihood value.
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