| 摘要 |
PROBLEM TO BE SOLVED: To eliminate the need for a steep filter such as a conventional one by using a directional coupler so as to separate signals of H and L channels. SOLUTION: A video camera 1, a modulator 2 providing an output of a high channel frequency, a video monitor 14, a demodulator 13 providing an output of a low channel frequency provided to a 1st terminal equipment, and a video camera 9, a modulator 10 providing an output of a low channel frequency, a demodulator 7 providing an output of a high channel frequency and a video monitor 8 provided to a 2nd terminal are connected via a transmission line 15 and the modulator 2 and the demodulator 13 of the 1st terminal equipment and the modulator 10 and the demodulator 7 of the 2nd terminal equipment are coupled with the transmission line via directional couplers 4, 5 respectively to transmit incoming and outgoing video signals using the frequency division multiplex system. Furthermore, balanced directional couplers are adopted for the directional couplers 4, 5.
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