| 摘要 |
PURPOSE:To eliminate uncertainty of a reference phase when a phase modulation signal is demodulated at a receiver side even when a QLI code is used for an error correction code. CONSTITUTION:After frame synchronization by a frame synchronization discrimination circuit 26 is established, an exclusive OR circuit 29 obtains a difference between a data string resulting from retarding an output of a phase converter 23 at a delay device 27 and a data string resulting from coding an output of a decoder 24 at a coder 28, a counter 30 counts the number of difference for a prescribed time, a code synchronization discrimination circuit 31 compares the count with a predetermined threshold level to discriminate code synchronization based on the result of comparison. Thus, uncertainty of demodulated reference phase is left depending on a pattern of a reception series resulting in causing possibly mis-synchronization in a conventional system but the phase uncertainty is eliminated completely in this system. |
