| 摘要 |
PURPOSE:To reproduce the correct hue without regard to the ambient temperature change, etc., by fixing the phase relation between an index signal and the dot sequential chromaticity signal of a triplet frequency on the basis of the phase relation between a sub-carrier and the dot sequential chromaticity signal. CONSTITUTION:A frequency conversion circuit 3A has a 3.58 MHz sub-carrier input terminal 35, index signal input terminal 36, 3.58MHz dot sequential chromaticity signal input terminal 37, triplet frequency dot sequential chromaticity signal output terminal 38, phase adjusting circuit 39, multiplication circuits 40 and 41, 1H delay circuit 42, the 1st and 2nd band pass filters 43 and 44 and a phase control terminal 45; and further, a detector 60 detecting the phase difference between the sub-carrier and the dot sequential chromaticity signal, phase adjusting device 62 adjusting the phase of the index signal, detector 61 detecting the phase difference between an index signal and a triplet frequency dot sequential chromaticity signal, and a voltage comparison control circuit 63 controlling a phase adjusting circuit 39 are installed so as to coincide the output of both detectors 60 and 61 with each other. |
