| 摘要 |
PROBLEM TO BE SOLVED: To realize inter-group communication at a low cost. SOLUTION: An image reduction device 30 reduces the image of a video signal from a video camera 18 (e.g. to 1/4). A video signal separator 14 separates a desired video signal on an image transmission line 12. A video changeover switch 32 switches an output video signal from the devices 30, 14. A vertical interval data signal(VIDS) coder 34 converts data or the like into a VIDS signal and an adder 36 is used to multiplex the output of the coder 34 onto an output video signal of the switch 32. An FM modulation circuit 38 applies FM modulation to an input audio signal and an adder 40 multiplexes the output of the adder 36 onto the output of the FM modulation circuit 38 and a video signal transmitter 16 sends the output of the adder 40 to the image transmission line 12. |
