| 摘要 |
PCT No. PCT/GB90/01758 Sec. 371 Date May 27, 1992 Sec. 102(e) Date May 27, 1992 PCT Filed Nov. 17, 1990 PCT Pub. No. WO91/08623 PCT Pub. Date Jun. 13, 1991.A passive optical network includes a head-end station and a plurality of terminations. The terminations are responsive to control signals from the head-end station. The head-end station is arranged to receive frames having a predetermined bit rate and comprising signals transmitted by the terminations. Ranging pulses are transmitted from each of the terminations to the head-end station where the received ranging pulses are sampled at a high sampling rate greater than the predetermined bit rate. The data samples are applied to a processor which determines the phase and amplitude of the ranging pulses and generates control signals for the terminations to modify the phase or timing and amplitude of the transmissions from the terminations. A locally generated marker pulse may be applied to the incoming data frame before it is sampled in the head-end station, the marker pulse providing a phase and amplitude reference for use by the control processor. |
