| 摘要 |
PURPOSE:To discriminate video reproduction and multi audio reproduction automatically by checking the presence of a vertical synchronizing signal of reproduced video signals, and deciding as video is in reproduction when the presence of a vertical synchronizing signal is detected, and deciding as multi audio is in reproduction when the absence of vertical synchronizing signal is detected. CONSTITUTION:Composite video signals are outputted at the time of video reproduction to an output 31 of a reproduced video signal processing circuit 12, and composite video signals are not outputted at the time of multi audio reproduction. Accordingly, a vertical synchronizing signal is outputted at the time of video reproduction to an output 32 of a vertical synchronizing signal separator circuit 17, and the vertical synchronizing signal is not outputted at the time of multi audio reproduction. A vertical synchronizing signal of the output 32 outputted at the time of video reproduction is smoothened by a smoothening circuit 18 and outputs a discriminating signal to an output 35. At the time of multi audio reproduction, the output 35 becomes zero potential. Accordingly, an output 36 of a switching circuit 19 is made to output zero potential at the time of video reproduction.
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