| 摘要 |
PROBLEM TO BE SOLVED: To eliminate an entry of external noise and damage to a transmission line, etc., due to lightning, to reduce the loss of a transmission line system, and to remove a handicap of communication in a tunnel, etc., by composing the transmission line of an optical fiber equipped with a light source and a photoelectric converter and equipping a repeater with a reception part composed of an optical modulator. SOLUTION: A radio wave radiated by a transmitter 8 in a closed space is converted from an electric signal to a light signal by the nearest repeater 9 among repeaters which are provided for the optical transmission line at constant intervals and composed of optical modulators. The light signal is propagated in the said transmission line consisting of the optical fiber laid in the space and made incident on the optical modulator 3. The light signal is reconverted by the optical converter 3 into an electric signal, which is amplified by an amplifier 5 and radiated as a radio wave into an open space from a transmitting antenna 1. The propagation loss of the transmission line of the optical fiber 6 is small, so the need for signal amplification is eliminated or the installation intervals can be made long. |
