| 摘要 |
A synchronizing circuit for a video disc playback device comprises a external signal processing system processing a video signal reproduced from a disc, a internal signal processing system processing an internal video signal to be superimposed on the video signal reproduced from the disc, a window establishing circuit for establishing a window including an expected timing of a synchronizing signal of the external signal processing system and a control circuit for controlling the internal signal processing system to synchronize with the external signal processing system. If a synchronizing signal from the external signal processing system has occurred in the window in the internal signal processing system, the expected timing of the synchronizing signal of the external signal processing system is used as the synchronizing signal of the internal signal processing system even if the actual synchronizing signal of the external signal processing system is deviated from the expected timing. The synchronizing circuit may further comprise a circuit for correcting the window when the synchronizing signal of the external signal processing system has occurred outside of the window. The synchronizing circuit may further comprise a time base correcting circuit for correcting time base of the reproduced video signal each time track-kick is performed and a time base reference changing circuit for compulsorily changing time base reference of the synchronizing system each time the track-kick is performed.
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