Eye monitoring and reconstruction using CDR and sub-sampling ADC

A method to construct an eye pattern from a serial data signal within a receiver of a serial data communication system, said method comprising:

• receiving a serial data signal with said receiver;
• generating a clock signal that is derived from said serial data signal within said receiver;
• generating timing data corresponding to phases of said clock signal within said receiver;
• sampling said serial data signal using said clock signal to generate sampled data within said receiver;
• and
• correlating said sampled data with said timing data to construct said eye pattern corresponding to said serial data signal.

An apparatus, within a receiver used in a serial data communication system, to construct and monitor an eye pattern from a serial data signal received by said receiver, said apparatus comprising:

• a first circuit to generate a first clock signal from said serial data signal;
• a second circuit to generate a second clock signal from said first clock signal;
• a third circuit responsive to said second clock signal to generate a third clock signal by shifting a phase of said second clock signal, and to generate a related phase position corresponding to a current phase of said third clock signal;
• a fourth circuit used to sample and hold said serial data signal, said fourth circuit generating an aligned serial data signal;
• an analog-to-digital converter (ADC) to generate sampled data values from said aligned serial data signal in response to said third clock signal;
• and
• a data processor responsive to said sampled values and said phase position data to generate said eye pattern.

A system to adaptively adjust receiver parameters of a receiver used for receiving a serial data signal in a serial data communication system, said system comprising:

• one or more circuits for generating an eye pattern from said received serial data signal, said eye pattern based on correlating a sampled data signal with a phase position signal, said phase position signal derived from a clock signal derived from said serial data signal, said sampled data signal generated from sampling said serial data signal using said clock signal;
• said one or more circuits for evaluating at least one pre-defined characteristic of said eye pattern, said evaluating comprising measuring said at least one pre-defined characteristic to generate at least one measured value and comparing said at least one measured value to at least one pre-defined test value;
• and
• said one or more circuits for adjusting at least one receiver parameter of said receiver based on said evaluating.

A system to construct an eye pattern from a serial data signal within a receiver of a serial data communication system, said system comprising:

• one or more circuits for receiving a serial data signal;
• said one or more circuits for generating a clock signal that is derived from said serial data signal;
• said one or more circuits for generating timing data corresponding to phases of said clock signal within said receiver;
• said one or more circuits for sampling said serial data signal using said clock signal to generate sampled data within said receiver;
• and
• said one or more circuits for correlating said sampled data with said timing data to construct said eye pattern corresponding to said serial data signal.