| 摘要 |
PURPOSE:To prevent a furtive glance of a video and to improve the security by providing a means to descramble a scrambled video intermediate frequency signal back to an original video intermediate frequency signal. CONSTITUTION:Signal suppression of a video carrier is executed in a video system circuit, and information to release this scrambling is transmitted by an audio carrier system circuit and a data transmission system circuit. Hence a microprocessor 40 supplies identification data to an FSK converter 42 to transmits it as a transmission signal. The signal arrived at an input terminal 50 is supplied to an up-down converter 52 and an FSK demodulator 71. Since the identification data is conducted from the demodulator 71 to a microprocessor 72, an original current video carrier can be obtained from a variable gain controlled amplifier 54. |
