| 摘要 |
PURPOSE:To eliminate interference and oscillation in a repeater under real-time transmission to improve the transmission quality by converting the frequency of a carrier by the repeater. CONSTITUTION:At the time of operating in up-link, each of repeaters 2, 2... receives the optical signal based on a (first) modulated signal, which is obtained by modulating 2MHz carrier wave (first carrier) by data, from a terminal 1 to generate 4MHz carrier wave (second carrier) and transmits it as an optical signal to a center terminal 3. At the time of operating in down-link, each of repeaters 2, 2... receives the optical signal based on the (first) modulated signal, which is obtained by modulating 2MHz carrier wave by data, from the center terminal 3 to generate 4MHz carrier wave and transmits it as an optical signal to the terminal 1. Since each repeater 2 changes frequencies of carrier waves of the reception signal and the transmission signal in the case of up-link as well as down-link in this manner when relaying optical signals, the occurrence of oscillation in the repeater 2 itself is prevented. |
