| 摘要 |
PURPOSE:To prevent the generation of pulse noise interference from a control part to a video signal, by allowing a control signal, etc., which may cause interference to the video signal to make them all present in a vertical flyback period. CONSTITUTION:A control clock signal 29 is inputted to a gate circuit 44 and a clock 45 required for antenna switching control is extracted by a gate signal 43 by a gate signal generating circuit 42 during a vertical flyback period on the basis of a vertical synchronizing pulse 41. Since a control reference signal generating circuit 30 inputs only the clock signal 45 in a limited period in the vertical flyback period, so control reference signals 31-33 are also present only in a limited period in the vertical flyback period and control signals generated from signals 31-33 are the same. Therefore, no influence upon a picture of TV is exerted. |
