| 摘要 |
PURPOSE:To obtain an image of high quality even when the DC level of a video signal is changed by providing this video descrambling device with a DC shifting circuit and executing descrambling signal processing in a DC direct connection state. CONSTITUTION:A scramble signal with compressed synchronizing part is DC- shifted by the DC shifting circuit 2 and simultaneously inputted to amplifiers 3 to 5 having respectively different synchronizing part compression ratios. A scrambling mode controller 10 detects which mode is applied to the synchronizing part compression ratio of the inputted scrambling signal and controls a mode switching circuit 6 to extract the output of the amplifier corresponding to the synchronizing part compression ratio. The output of the circuit 6 is outputted as a descrambled image signal output 7 and inputted to a TV image receiver. Even when the DC level of a video signal on the transmitting side is changed due to a change in the degree of modulation or the like, an apparent change in a pedestal level is removed and the quality of an image is improved. |
