| 摘要 |
PURPOSE:To attain a fine adjustment for the phase of a carrier chrominance signal with a simple circuit constitution by providing a phase switching circuit which switches the phase of a modulation operation at the modulation part of a color difference signal, and a delay circuit which adjusts the delay time of a composite color signal. CONSTITUTION:Color difference signals I and Q are supplied to a multiplexer 3 directly or through inversion circuits 1 and 2. A selection pulse generation circuit 4 generates selection pulses of four phases A-D, and a phase switching circuit 7 generates new selection pulses A'-D' replacing the order of the selection pulses A-D, and at the multiplexer 3, the I, the Q, the inverse of I, and the inverse of Q are selected, and carrier chrominance signals, the phases of which are delayed by every pi/2, are outputted. The carrier chrominance signal and a luminance signal Y are added at an adder 5, and an operating clock delayed at a clock delay circuit 9 is supplied to a D-FF10, and a digital composite color signal is delayed by tau, and is outputted as an analog composite color signal from a D/A converter 6. A micro adjustment for the phase of the carrier chrominance signal is performed by adjusting a clock delay time tau.
|
