Upstream data recovery and data rate detection

A method for recovering a data rate for an upstream burst transmission transmitted on a passive optical network at any one of a plurality of data rates:

• a) providing the upstream burst transmission to a plurality of data rate recovery circuits, each data rate recovery circuit operating at a different clock rate and each data rate recovery circuit;
• i) oversampling the upstream burst transmission using multiple register banks each sampling the upstream burst transmission at a different sampling point,
• ii) in response to oversampling, identifying an optimal sampling point for the clock rate of the data rate recovery circuit and identifying the register bank producing the optimal sampling point, and
• iii) deserializing an output from the identified register bank to produce a deserialized upstream burst transmission from the data rate recovery circuit;
• and
• b) analyzing the deserialized upstream burst transmission from each of the data rate recovery circuits to identify the data rate for the upstream burst transmission;
• and
• providing to each of the data rate recovery circuits a different clock signal and phase shifted clock signal pair.

An apparatus for identifying a data rate of an upstream transmission, the apparatus comprising:

• a first assembly comprising,
• a first clock signal generator capable of generating a first clock signal and a first phase shifted clock signal,
• a first plurality of register banks each capable of receiving at least one of the first clock signal and the first phase shifted clock signal to oversample the upstream transmission at a different phase offset of the clock signal,
• a first edge transition detection circuit having logic circuits to determine an edge transition state for each of the first plurality of register banks, and
• a first clock selection circuit coupled to the first edge transition detection circuit to identify a first optimal sampling point based on the edge transition states from the first plurality of register banks and to identify which of the first plurality of register banks samples the upstream transmission at the first optimal sampling point;
• and
• a second assembly comprising,
• a second clock signal generator capable of generating a second clock signal and a second phase shifted clock signal, where the rate of the second clock signal is different than the rate of the first clock signal,
• a second plurality of register banks each capable of receiving at least one of the second clock signal and the second phase shifted clock signal to oversample the upstream transmission at a different phase offset of the clock signal,
• a second edge transition detection circuit having logic circuits to determine an edge transition state for each of the second plurality of register banks, and
• a second clock selection circuit coupled to the second edge transition detection circuit to identify a second optimal sampling point based on the edge transition states from the second plurality of register banks and to identify which of the second plurality of resister banks samples the upstream transmission at the second the optimal sampling point.

An optical network device for identifying data rates of burst transmissions transmitted in an optical network, the optical network device comprising:

• an optoelectronic receiver to receive the burst transmissions;
• and
• data rate recovery circuits to receive the burst transmissions from the optoelectronic receiver, wherein each data rate recovery circuit comprises
• a first circuit having a plurality of registers to oversample the burst transmissions at different phase points of a clock signal,
• a second circuit to determine edge transition states between the different phase points of the clock signal, and
• a third circuit to identify an optimal sampling point based on the edge transition states, wherein each data rate recovery circuit samples the burst transmissions at a different clock rate,
• wherein each data rate recovery circuit further comprises a clock generator circuit to i) receive a downstream clock signal of the optical network device, ii) produce the clock signal for the data rate recovery circuit, and iii) produce a phase shifted clock signal for the data rate recovery circuit.