A data-signal-recovery circuit includes a flip-flop and a controller. The flip-flop has an adjustable sampling threshold, and, in response to a sampling clock, is operable to generate a recovered digital signal having a first level if an input data signal is above the threshold and having a second level if the input data signal is below the threshold. The controller is operable to adjust the threshold and phase shift of the sampling clock. Because the flip-flop has an adjustable sampling threshold, one can calibrate the flip-flop to the characteristics of the eye pattern at the flip-flop's input node.