| 摘要 |
PURPOSE:To project plural kinds of signals on the same screen by clamping two TV signals and controlling their brightness levels independently, and performing gain control over only one TV signal. CONSTITUTION:The 1st TV signals inputted from input terminals 1(1R-1B) are clamped by clamping circuits 6(6R-6B), brought under the brightness level control of brightness control circuits 9(9R-9B), and inputted to gain control circuits 12(12R-12B). Gain control circuits 12 vary gains according to a control signal from an input terminal 13 to obtain level-lowered TV signals. The 2nd TV signals inputted from input terminals 2(2R-2B), on the other hand, are applied directly to switching circuits 3(3R-3B) through clamping circuits 7(7R-7B) and brightness control circuits 10(10R-10B) and switched there with the outputs of the gain control circuits 12 by a switching signal inputted from a switching signal input terminal 4 to be outputted to output terminals 5(5R-5B). |
