| 摘要 |
PURPOSE:To add a great deal of data to a television signal and to simplify detection of the data by scrambling a horizontal synchronizing signal of the period except the one part of a vertical blanking period of the television signal or a horizontal blanking period in accordance with the logic level of the prescribed data. CONSTITUTION:A video signal S0 which is supplied to an input terminal 1 on the transmission side of a scramble system is added to a level matching circuit 3 as it stands, and a signal -S0 which is inversed by an inversion circuit 2 is also added to the circuit 3. After pedestal levels of the signals S0 and -S0 are matched by the circuit 3, the signal S0 is added to a contact (a) of the switch 4 and the signal -S0 is added to a contact (b). A switch pulse P4 which controls the switching of the switch 4 is supplied by an AND gate 7. The pulse P4 is formed by the logic of a timing pulse P1 of a timing circuit 6 which is driven by the signal HP separated by a synchronizing separator circuit 5 and a vertical synchronizing signal VP, and a pulse P2 from a controller 8. Scrambling is executed in accordance with the logic level of the data.
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