| 摘要 |
<p>PURPOSE:To adjust a picture level with high accuracy and simple constitution by driving each DA conversion circuit by a common DC voltage so as to vary the DC voltage. CONSTITUTION:When the video signal level is desired to be varied, a variable resistor 6 is varied, then the DC voltage V fed to each DA conversion circuit is changed entirely by the same ratio and as a result, the level of an obtained analog output signal level is changed by the same ratio with the DC voltage V. Thus, R, G, B signals being outputs of a matrix circuit 3 are varied by the same ratio without distorting the color balance and the level is changed while keeping the accurate color reproducibility. Thus, the circuit constitution is very simple and the level is adjusted accurately without distorting the color balance.</p> |
