| 摘要 |
PURPOSE:To prevent malfunction by attenuating or annihilating a regenerated clock in every horizontal synchronizing period. CONSTITUTION:When a burst signal is applied to an input terminal 1, a crystal oscillator 3 is driven to generate a ringing signal at a load resistance R2, and the signal is turned and amplified by a transistor (TR) Q2 and a transformer T2 and sent as a clock output to an output terminal 7. Part of this clock output reaches an adjusting circuit 5 through an AND gate 9. The adjusting circuit 5 adjusts its phase and level lastly, and the clock output is impressed to the crystal while 180 deg. out of phase with the output ringing of the crystal oscillator 3 and having such a level that attenuation is excellent. Consequently, the ringing generated by the crystal oscillator 3 is attenuated or annihilated in the arrival period of the horizontal synchronizing signal and no influence upon the next regenerated clock is exerted. |
