US Patent 9800438 Built-in eye scan for ADC-based receiver

An example method of performing an eye-scan in a receiver includes: generating digital samples from an analog signal input to the receiver based on a sampling clock, the sampling clock phase-shifted with respect to a reference clock based on a phase interpolator (PI) code; equalizing the digital samples based on first equalization parameters of a plurality of equalization parameters of the receiver; adapting the plurality of equalization parameters and performing clock recovery based on the digital samples to generate the PI code; and performing a plurality of cycles of locking the plurality of equalization parameters, suspending phase detection in the clock recovery, offsetting the PI code, collecting an output of the receiver, resuming the phase detection in the clock recovery, and unlocking the equalization parameters to perform the eye scan.