| 摘要 |
PURPOSE:To secure the selective generation for the color difference output of either one of the PAL and SECAM systems through a simple constitution, by varying the color difference signal DC voltage of the system decision generator circuit to make conduct either one of the PAL and SECAM system switch circuits. CONSTITUTION:System decision signal generator circut 9 and 10 decides whether the signal under reception is of the PAL or SECAM system. And switch circuit 3 and 4 are provided between synchronous detection circuit 1 and 2 of PAL color demodulator circuit 21 and output terminals 5 and 6, and switch circuit 10 and 11 are provided between FM detection circuit 7 and 8 of SECAM color demodulator circuit 22 and output terminal 12 and 13 respectively. Here, the color difference signal DC voltage of circuit 9 is varied to make conduct either one of the circuits 3 and 4 plus 10 and 11. Thus, either one of color difference output processed through circuit 21 and 22 is generated selectively through a simple constitution at the color difference signal output terminals connected in common and in accordance with the output of circuit 9. |
