| 摘要 |
PURPOSE:To correct automatically a signal level of every color by supreposing a pilot signal for AGC control on the signals of respective transmission systems of the three primary colors. CONSTITUTION:Color signals R, G, and B are supplied to terminals 3, 4, and 5 of a transmission side 1 and supplied to mixers 7, 8, and 9. A synchronizing signal is applied to a terminal 6 and converted by a shaping circuit 13 into a pulse signal which contains none of the color signals as shown in a figure C, and the converted signal is applied to the mixers 7, 8, and 9 respectively. Electrooptic converting circuits 10, 11, and 12 convert electric signals from the mixers into light signals, which are sent out through optical fiber cables 14, 15, and 16. A reception side 2, on the other hand, separates the pulse signals superposed on the transmission side by respective gate circuits and level comparators to control the gains of variable gain amplifying circuits 20, 21, and 22 inserted into respective systems according to the levels of the separated pulse signals. |
