| 摘要 |
PURPOSE:To obtain a clock signal with accurate and sufficient amplitude at the 2nd clock part, by suppressing an oscilltion of a ringing amplifier, before the 2nd character broadcast signal is incoming. CONSTITUTION:From a video signal multiplexed with a character broadcast signal applied to a terminal 21, only a signal for a burst clock part is picked up at an amplifier 23 by a gate pulse applied to a terminal 24. This clock signal has a basic frequency about a half the frequency of a transmission rate of a character broadcast signal, and a sampling clock is obtained by multiplying the signal. A signal from the amplifier 23 is applied to a ringing amplifier 26 and outputted via a buffer amplifier 28 as a continuous wave, wherein the oscillation energy of a quartz oscillator 27 is attenuated by applying an output of the buffer amplifier 28 to the ringing amplifier 26 via a phase inverting amplifier 31 just before the clock part is applied. |
