| 摘要 |
PCT No. PCT/GB90/00157 Sec. 371 Date Aug. 16, 1991 Sec. 102(e) Date Aug. 16, 1991 PCT Filed Feb. 2, 1990 PCT Pub. No. WO90/09709 PCT Pub. Date Aug. 23, 1990.An optical communications system comprises a transceiver arranged to provide two-way communication over an optical communications channel (3). The transceiver comprises a semiconductor light source (4) and a detector (5). The semiconductor light source (4) provides optical signals for transmission via the optical communications channel (3), and the detector (5) detects optical signals received via the optical communications channel and converts said optical signals into electrical signals. Means (2)a, (2)b) are provided for modulating the output of the semiconductor light source (4) with an RF carrier having a first frequency. Said electrical signals are passed through filter (8) adapted to filter out signals at said first frequency. |
