| 摘要 |
PROBLEM TO BE SOLVED: To transmit an information signal only with a reference signal terminal without the need for an exclusive terminal by providing a superimposing output circuit having a superimposing circuit and a bypass relay circuit and connecting an input terminal and an output terminal in loop-through connection. SOLUTION: A superimposing circuit 12 of a superimposing output circuit 4 receives a reference signal from an input terminal 2 via a buffer amplifier (BA) 11 and a superimposing signal from a superimposing signal generating circuit 7 receiving an information signal and an information data signal generated by a video device main circuit 6, and an amplifier circuit 13 drives and outputs the reference signal with the superimposing signal superimposed thereon. A bypass relay circuit 14 selects an output from the amplifier circuit 13 or the reference signal from the input terminal 2 and outputs the selected signal to an output terminal 3. Then a bypass state of the input output, that is, the loop-through connection is attained as required by a control signal from the video device main circuit 6.
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