| 摘要 |
PURPOSE:To perform accurate color demodulation, by obtaining continuous phase of each sub-carrier during each double speed scanning period, in a double speed scanning television receiver which twice scans signals substantially equal with each other obtained from signals during horizontal scanning period. CONSTITUTION:A double speed scanning signal S2 from a terminal 26 becomes a chroma signal SC1 through a band pass amplifier 9 and is connected to a contact (a) of a switch 29 and to a contact (b) via an inverter 30. The switch 29 is changed over at each 1H with a switching pulse PG applied to a terminal 27. Thus, the phase of sub-carrier of an output signal SC2 of the switch 29 is inverted at each 1/2H. On the other hand, a burst SB is picked up from the signal SC1, which drives a sub-carrier oscillator 17. Then, the phase of the sub-carrier is continuous in each scanning line and chroma signals R, G and B with correct demodulation can be obtained from a color reproducing circuit 25. |
