| 摘要 |
PURPOSE:To simplify a data taking-out circuit by using a synchronizing signal in a video signal of a TV as a clock. CONSTITUTION:In the transmission side, the carrier modulated by data whose change point is synchronized with an integral multiple or 1/(an integer) of a horizontal synchronizing signal of the video is provided in the sound band of the television signal. In the reception side, an audio carrier is detected in a sound detecting part 11 to extract a sound signal and a subcarrier, and the subcarrier is sent to a subcarrier detecting part 13 through a filter 12. Extracted data is inputted to a data processing part 14. A video signal and the synchronizing signal are extracted in a video detecting part 16, and the synchronizing signal is separated by a synchronizing signal separating circuit 15 and is inputted to the data processing part 14. The data processing part 14 generates a sampling clock in accordance with the synchronizing signal.
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