摘要 |
In a signal transmission system made up of a transmission section, a receive section and an optical fiber installed between the transmission section and the receive section, a harmonic producing circuit and a harmonic phase shifting circuit are provided on the downstream side of an FM modulator. The harmonic producing circuit superimposes a harmonic of an FM signal on the FM signal, and the harmonic phase shifting circuit shifts the phase of the harmonic. This arrangement compensates a group delay deviation occurring in system components when an AM signal or QAM signal is modulated into an FM signal or PM signal in a modulator and then transmitted to be demodulated in a demodulator, thereby improving transmission quantity.
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