| 摘要 |
PURPOSE:To constitute so that the phase of a horizontal synchronizing signal and that of an oscillating signal are made to coincide with each other when mean voltage of a capacitor has become the lowest value, by making a phase detecting characteristic have linearity extending over a 1H period. CONSTITUTION:When a pulse P1 from a pulse generator 28 is applied to the base of a transistor (TR) Q21, TR Q21 is turned on. In a capacitor C21, VA- VD are held. Also, when a pulse P2 from the generator 28 is applied to the base of TRQ23, TRQ23 is turned on, and VA-VD-R0I0 are held in the capacitor C21 through TRQ30. When a horizontal synchronizing signal SH is applied to the base of TRQ25, VA-VD-R0I0 are held in the capacitor C21 in case when an oscillating signal of the generator 28 is high, and VA-VD-2R0I0 are held in C21 in case when said signal is low. When mean voltage of the capacitor C21 sets the lowest value to VA-VD-R0I0, the mean voltage becomes above or below said lowest value due to a phase difference of the oscillating signal S0 and the horizontal synchronizing signal SH, but at the time of the lowest value, both phases become in coincidence. |
