| 摘要 |
PROBLEM TO BE SOLVED: To differentiate ciphering degree of image information for each reception station and to prevent illegal decoding by incorporating a random number generating circuit and a circuit for setting an initial state to be an optional value in an integrated circuit. SOLUTION: An initial value is set to a 1st address generating circuit ADH 9 so that head data of scramble data are a switching point by using a random number generating circuit 7, an address is given to a 1st memory circuit 16 through a 1st selection circuit 12 and data by one horizontal period are written through a 3rd selection circuit 14. Data are read from the circuit 16 according to a 2nd ADH 10 for a succeeding period and outputted to an output terminal 6 through the circuit 14, an initial value is set to the circuit 9 by using the circuit 7 and an address is given to a 2nd memory circuit through a 2nd selection circuit 13 and data are written through a 4th selection circuit 15. Data are read from a circuit 17 according to the circuit 10 for a succeeding horizontal period and outputted to the output terminal 6 via the circuit 15 and the circuit 7 is used to set an initial value to the circuit 9 and an address is set to the circuit 16 to write data by one horizontal period. |
