Method and apparatus for controlling timing of a transmission signal from a network termination device

An apparatus for controlling timing of an upstream transmission from an optical network termination device to an optical line termination device in a passive optical network, the apparatus comprising:

• a receiver to receive a downstream transmission from the optical line termination device, and to analyze the downstream transmission to recover a reference clock, and to determine a core clock signal for the receiver based on the recovered reference clock;
• and
• a transmitter to (i) form the upstream transmission based on processing of the downstream transmission, and (ii) produce a phase offset signal to control conversion of the core clock signal to a transmitter clock signal offset, the transmitter including
• a phase adjusted clock signal generator to receive the core clock signal from the receiver and generate a transmitter clock signal, and
• an upstream framing controller coupled to the phase adjusted clock signal generator to control phase of the transmitter clock signal,
• wherein the transmitter clock signal offset is used in timing the transmission of the upstream transmission.

A network termination device comprising:

• a first transceiver to receive a downstream transmission having a first bit rate;
• a receiver circuit coupled to the first transceiver, the receiver circuit to recover a reference clock based on the downstream transmission and to determine, based on the recovered clock, a core clock signal for the receiver circuit;
• a transmitter circuit to form an upstream transmission, the transmitter circuit having a transmitter clock signal to be used in transmitting the upstream transmission, wherein the transmitter clock signal is offset from the core clock signal, wherein the transmitter circuit includes
• a phase adjusted clock signal generator configured to (i) receive the core clock signal from the receiver circuit and (ii) generate the transmitter clock signal, and
• an upstream framing controller configured to control generation of the transmitter clock signal;
• and
• a second transceiver to communicate the upstream transmission.