| 摘要 |
PURPOSE:To obtain a synchronizing signal reproduction circuit with high reliability by supplying a timing pulse generated at a timing generation means to a synchronizing signal detection means, and detecting one synchronizing signal out of plural synchronizing signals. CONSTITUTION:A timing generation circuit 6 monitors a timing, and outputs a gate signal 15 for an SYNC detection, and supplies it to an SYNC detection circuit 8. One additional timing pulse is generated by adding a counter 62, an AND circuit 64, and an OR circuit 65, and when it is impossible to detect an original SYNC, a backup SYNC can be detected. By adding both timing pulses 15 to the SYNC detection circuit 8, either one of an SYNC 2 or an SYNC 2' can be detected at the SYNC detection circuit 8. The output of a demodulation circuit 9 is inputted to an error control circuit, and after an error is corrected, it is outputted to an output device, such as a display device or a printer. Thereby, the synchronizing signal reproduction circuit with high reliability can be obtained.
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