| 摘要 |
PURPOSE:To provide a control circuit which can on/off-control the operation of a copy preventing circuit for an image signal. CONSTITUTION:A diagram shows the circuit which on/off-controls a copy inhibiting operation. When the copy inhibiting operation is touned on, a process ON signal is made high, the output of FF17 is made high and the copy inhibiting operation is executed by the output. At that time, a prescribed ON key code is inputted to a register 11, and a code obtained by modulating the code by a modulator 12 is latched to FF 13. For making the output of FF17 which is once made high to be low, the process ON signal is made low and an OFF KEY code whose value is equal to the latch output of FF13 is inputted to a register 14. The code is latched by FF15 and is compared with the output of FF13. Only when they are matched, FF 17 is reset by comparison output and the output becomes low. Thus, a copy inhibiting state is released. |
