| 摘要 |
PURPOSE:To realize the application of the generated clock signals through other circuits except a dividing circuit and at the same time to shorten the phase matching time, by applying a clock signal oscillated fixedly to the dividing circuit via a switch circuit for stop and continuous controls of the dividing actions of the dividing circuit to perform a phase matching action. CONSTITUTION:A clock generating circuit 10 produces a clock signal having a frequency of an integer multiple as mush as a color subcarrier frequency synchronous with a color burst signal based on a video signal and applies the clock signal to a dividing circuit 13 via a switch circuit 12. The circuit 13 divides the clock signal for production of the output horizontal drive pulses. While a reference horizontal drive pulse generating circuit 11 produces separately the reference horizontal pulse signals from the video signals VID. A switch control circuit 14 turns on and off the circuit 12 in accordance with the phase shift between the reference horizontal drive pulse and the output horizontal drive pulse to match the phases with each other between both pulses. Thus it is possible to obtain a horizontal drive pulse generating circuit of a simple constitution that can be applied by other circuits with no influence of the phase shift between both horizontal drive pulses given to the generated clock signal.
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