| 摘要 |
PURPOSE:To make the discrimination of identifying signal easy and to prevent the malfunction, by detecting and discriminating the amplitude switching and controlling signal added in front of the wide screen use TV signal for the amplitude control. CONSTITUTION:The video intermediate output fed to the terminal 1 is fed to the band pass amplifier 11 to pick up the intermediate output SS' for amplitude switching, and fed to the slice circuit 12 to output only the intermediate output having the level of reference level or more. The output of the circuit 12 is fed to the amplifier 13, and the output of the amplifier 13 is detected at the detection circuit 15, it is fed to the wave shape circuit 17 via the integration circuit 16 to form the detection output SD. The output SD is fed to the forming circuit 18 of the amplitude switching control pulse SP, the output is fed to the horizontal deflection circuit system 6 to extend the horizontal amplitude. Thus, the wide screen with the wide screen TV signal SW' is displayed. After that, the input of the signal SW' is disconnected and the signal SS' suceeding to it is input, allowing to switch the screen from wide to normal screen. |
