| 摘要 |
PURPOSE: A code rate detecting device is provided to finish the synchronization detection in a short time by comparing the number of times that a current path matric having a matric smallest value equals to an estimation path matric for next transition. CONSTITUTION: A code rate detecting device includes a selecting part(11) for selecting a code rate among a plurality of code rates. An adding/comparing selection part(13) adds branch matrics of a current state to path matrics accumulated with branch matrics corresponding to each state node by the selected code rate and compares the path matrics of the state nodes of the current state, thereby outputting a current state path matric having a smallest value. An estimation path matric calculation part(15) calculates an estimation path matric to which the path matric having the smallest value transits next. A first comparator(17) compares the estimation path matric with the current state path matric. If the path matrics are not equal, a counter(19) counts how many number of times the matrics are not equal, thereby outputting an error number. A second comparator(21) compares the output error number with a reference number for a predetermined time. If the error number is smaller, the second comparator outputs an activated synchronizing signal representing the code rate selected by the selecting part is equal to a code rate encoded by a transmission terminal. In the other case, a non-activated synchronizing signal is selected for the selecting part to select any other code rate than the previously selected one.
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