Method and system for link jitter compensation including a fast data recovery circuit
A method and apparatus, in some embodiments the apparatus includes a sampler, using a plurality of sampling clocks, to sample a first set of data of an incoming data signal to determine a first phase shift indicator and to sample a second set of data of the incoming data signal to determine a second phase shift indicator, a data recovery circuit (DRC) including control logic to determine a phase control signal based on the first and the second phase shift indicators, and a phase interpolator to receive the phase control signal and adjust a phase of the sampling clocks, wherein the phase interpolator provides the plurality of sampling clocks.
1. An apparatus comprising:
a sampler, using a plurality of sampling clocks, to sample a first set of data of an incoming data signal to determine a first phase shift indicator and to sample a second set of data of the incoming data signal to determine a second phase shift indicator, wherein the first set of data is a data bit-(N) and a data bit-(N+1), and the second set of data is a data bit-(N+1) and a data bit-(N+2);
a data recovery circuit (DRC), and not an alignment circuit and a proportional filter circuit, the DRC including control logic to determine a phase control signal based on the first and the second phase shift indicators alone and not in combination with a separate reference clock, wherein the DRC operates at about a rate half of the incoming data signal; and
a phase interpolator to receive the phase control signal and adjust a phase of the sampling clocks, wherein the phase interpolator provides the plurality of sampling clocks.
2. The apparatus of claim 1 , wherein the DRC adjusts the phase of the sampling clocks to align successive sets of data sampled from the incoming data signal.
3. The apparatus of claim 1 , wherein the DRC does not align the first set of data or the second set of data with a reference clock signal.
4. The apparatus of claim 1 , further comprising a serial input parallel output converter coupled to an output of the sampler.
5. The apparatus of claim 1 , wherein the DRC has a processing latency of about 1 period of the incoming data signal.
6. A method comprising:
sampling a first set of data of an incoming data signal to determine a first phase shift indicator using a plurality of phases of a plurality of sampling clocks;
sampling a second set data of the incoming data signal to determine a second phase shift indicator using a plurality of phases of the plurality of sampling clocks, wherein the first set of data is a data bit-(N) and data bit-(N+1), and the second set of data is data bit-(N+1) and data bit-(N+2);
determining, using a data recovery circuit (DRC) logic device and not an alignment circuit and a proportional filter circuit, a phase control signal based on the first and the second phase shift indicators alone and not in combination with a separate reference clock, wherein the DRC operates at about a rate half of the incoming data signal; and
providing the phase control signal to a phase interpolator to adjust a phase of the sampling clocks that are provided thereby.
7. The method of claim 6 , wherein the determination of the first phase shift indicator is based on a transition between data bit-(N) and data bit-(N+1), and the determination of the second phase shift indicator is based on a transition between data bit-(N+1) and data bit-(N+2).
8. The method of claim 6 , wherein the DRC does not align the first set of data or the second set of data with a reference clock signal.
9. The method of claim 6 , further comprising amplifying the incoming data signal prior to sampling the sampling.
10. The method of claim 6 , further comprising providing a serial input parallel output converter coupled to an output of the sampler to provide a recovered data signal.
11. The method of claim 6 , wherein the phase control signal provides an indication to advance, to retard, or not to adjust the phase of the sampling clocks provided by the phase interpolator.
12. The method of claim 6 , wherein the DRC logic device does not receive an input of a reference clock signal.
13. The method of claim 6 , wherein the DRC logic device has a processing latency of about 1 period of the incoming data signal.
14. A system comprising:
a wireless transmitting device synchronized to a first clock; and
a receiving device coupled to the transmitting device and synchronized to a second clock, the receiving device comprising:
a sampler, using a plurality of sampling clocks, to sample a first set of data of an incoming data signal to determine a first phase shift indicator and to sample a second set of data of the incoming data signal to determine a second phase shift indicator, wherein the first set of data is a data bit-(N) and a data bit-(N+1), and the second set of data is a data bit-(N+1) and a data bit-(N+2);
a data recovery circuit (DRC), and not an alignment circuit and a proportional filter circuit, the DRC including control logic to determine a phase control signal based on the first and the second phase shift indicators alone and not in combination with a separate reference clock, wherein the DRC operates at about a rate half of the incoming data signal; and
a phase interpolator to receive the phase control signal and adjust a phase of the sampling clocks, wherein the phase interpolator provides the plurality of sampling clocks.
15. The system of claim 14 , wherein the sampling clocks are derived from the second clock.
16. The system of claim 14 , wherein the DRC adjusts the phase of the sampling clocks to align successive sets of data sampled from the incoming data signal.