| 摘要 |
PURPOSE:To make a circuit simple in structure and small in size by having a mixing circuit to mix an output of a modulating circuit and an input video signal, an insulating circuit part to supply the output of the mixing circuit and insulate the signal at the input side and the signal at the output side and an amplifying circuit connected to the output side of the insulating circuit part. CONSTITUTION:From a sound signal source 6, a sound signal is FM-modulated to 4.5 MHz by an FM modulating circuit 10, supplied to a mixing circuit 10, and here, mixed with the video signal from a vedeo signal source 1. By FM- modulating in the FM modulating circuit 10, the video signal and sound signal are the same signal shape as the intercarrier system detecting output signal of the television receiver. A mixing output from the mixing circuit 10 is supplied through a transformer driving circuit 3 and an insulating transformer 4, here amplified and supplied to the circuit at the rear step. Thus, sincethe FM- modulated sound signal and the video signal and mixed, one insulating transformer can be sufficient. |
