抄録
Numerous TV relay stations are required for digital terrestrial broadcasting services in mountainous regions and these are expensive to construct. To reduce their cost, we propose a system that can retransmit UHFband terrestrial digital TV signals (OFDM<Orthogonal Frequency Division Multiplex> signals: nine channels) sent via long-distance (340km) optical-fiber networks. Weverified its exceptional performance through experiments. This system uses an LD direct optical modulator to reduce the construction costs and has a high equivalent C/N of about 40dB and very low distortion, which are traditionally considered to be very difficult to achievewith direct modulation. We attained these by adopting an optimum design to acquire a high C/N and wavelength dispersion compensation to transmit the OFDM signals.
