| 摘要 |
When transmitting an audio signal by multiplexing in a synchronous period of a video signal, a buffer memory for time axis adjustment of the audio signal is controlled. The number of audio signal samples in the buffer memory is detected in every n fields (n being a positive integer) of video signal, and when it is different from a specific value, the read or write address of the buffer memory is preset, so that the number of audio signal samples in the buffer memory is kept constant at the moment of inspection in every n fields. Besides, by inspecting the number of audio signal samples in the buffer memory in one field or more, a line providing a maximum or minimum value of the number of samples is stored, and thereafter the number of audio signal samples in the buffer memory in that line is kept constant, so that the buffer memory capacity may be utilized effectively. As a method of recovering isochrony of the video and audio signals, at the transmission side, the delay time of the audio signal with respect to the video signal of a predetermined video line is kept constant, and, at the reception side, the video signal is delayed on the basis of the delay time of the audio signal with respect to the video signal in that line.
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