| 摘要 |
PURPOSE:To reduce W bar adding circuits and the trouble of an adjustment of the amount of W bar addition by adding bar W and red, green and blue bars, held at the same level, via a Y matrix circuit. CONSTITUTION:Bars R, G and B from R, G and B bar generating circuits 1-3, after stored in buffer circuits 11-13 temporarily, are inputted to the emitter of transistor TR17 via Y matrix resistances 14-16. When R, G and B bar levels inputted to TR17 are denoted as ER, EG and EB respectively, resistances 14-16 have prescribed values to load resistance 20 so that composite output waveform level EY will be as shown by the equation. For this purpose, output bar W of W bar generating circuit 4 is stored in buffer circuit 23 temporarily, deficiency in level in an EBU white color bar period is compensated at the ratio of resistances 24 and 20. Thus, an EBU Y bar signal appears at output terminal 22. |
