| 摘要 |
PURPOSE:To output burst gate pulse precisely without influence of noise by providing a monostable multivibrator generating pulse having pulse width shorter than a horizontal synchronizing signal and longer than the period obtained by subtracting a burst signal from the horizontal synchronizing signal in a burst gate pulse generating circuit. CONSTITUTION:A signal recorded in a recording medium 1 is read out by a signal converting device 2 and demodulated by an FM demodulator to obtain a demodulating video signal 12. A synchronous separating circuit 7 samples a horizontal synchronizing signal 15. A monostable multivibrator A8 delays the horizontal synchronizing signal 15 by T1 and monostable multivibrator B9 generates a pulse with the pulse width of T2 as a burst gate pulse 17. If the pulse width T3 of a monostable multivibrator C18 is set up shorter than the horizontal synchronizing signal and longer than the period obtained by subtracting the burst signal period from the horizontal synchronizing signal and the period is made a nonsensitive period, no output is generated to a noise 15a. Even if a noise exists preceding a horizontal synchronizing signal, the burst output is not influenced, and a color shading is small. |
