| 摘要 |
PURPOSE:To allow a limited subscriber only to attain reception by applying scrambling to the order of a video signal at the transmission side, transmitting the result and applying descrambling it at the reception side. CONSTITUTION:Switches 21-24 are transmission/reception changeover switches and Fig. shows the transmission state. When an address to read a video image data of a memory 3 changes according to, e.g., Table (a) by a V address converting circuit (scramble circuit) 17 at the transmission side, the order of the video image at the transmission side output is at random as shown in Fig. (b). Further, in this case, in order to prevent that the continuity of the burst is lost, a burst is inserted at the output side. In the reception side (the position of the switches 21-24 is opposite to the position shown in Fig.), the order of the random video image is inverted by a V address converter (descramble circuit) 18. Moreover, a flag detection circuit 11 detects a flag and gives it to a write V address generator 9 when no write address correction is executed at the reception side.
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