| 摘要 |
PURPOSE:To fix a PAL switch to a prescribed phase, by providing a switch means interlocked with the switching of the PAL and the NTSC, and a means tentatively changing the voltage of an output hold capacitor at the reception of NTSC. CONSTITUTION:At the reception of a PAL signal, switch contacts are selected to e1, e3. Thus, a horizontal pulse P2 is applied to an FF15 and inverts the on-state of TRsQ1, Q2. Further, a set means 26 receives no action, a capacitor 22 is charged when the output of a phase detector is in the burst gate pulse P1, the level at point F is increased to be a killer level or over. A voltage V1 is set to an ID level and a voltage V2 is set to the killer level. At potential at point F <V1, ID operation is excuted and when the level is lower than the V2, the color killer operation is executed. At the reception of the NTSVC signal, a horizontal pulse P2 for trigger is made ineffective, and an FF15 stops inversion. Further, at potential of point F>V1 at the set means 26, the reset of FF1 is unchanged. At potential of point F>V2, a chroma signal is outputted. |
