| 摘要 |
PURPOSE:To obtain a sufficient S/N by providing a wire transmission equipment, which subjects a video signal to frequency modulation with a modulator set to <=1.0 modulation index occupying a frequency band width same or narrower than the band required for two channels of wire transmission. CONSTITUTION:The video signal is inputted to an emphasizer 2 from an input terminal 1 and is subjected to preemphasis for frequency modulation by a frequency modulator 3 and has the band limited by a band-pass filter 4. This signal has the upper sideband eliminated by the band-pass filter 4 and is outputted to a transmission line 6 through an output amplifier 5 or the like and is inputted to a limiter 8 through an input amplifier 7. The lost upper sideband is reproduced from the lower sideband by a very hard limiting before demodulation in a frequency demodulator 9. The signal obtained by the limiter 8 is demodulated by the frequency demodulator 9 and is subjected to deemphasis in a deemphasizer 10, and the original video signal is obtained in an output terminal 11. |
