PASSIVE OPTICAL NETWORK

摘要

A passive optical network includes a head-end station (1) and a plurality of terminations (2). The terminations (2) are responsive to control signals from the head-end station (1). The head-end station (1) is arranged to receive frames having a predetermined bit rate and comprising signals transmitted by the terminations (2). Ranging pulses are transmitted from each of the terminations (2) to the head-end station (1) 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 (7) which determines the phase and amplitude of the ranging pulses and generates control signals for the terminations (2) to modify the phase or timing and amplitude of the transmissions from the terminations (2). A locally generated marker pulse may be applied to the incoming data frame before it is sampled in the head-end station (1), the marker pulse providing a phase and amplitude reference for use by the control processor.