Receiving device and operating method thereof

A receiving device comprising:

• a delay buffer configured to receive an analog signal and output a delayed analog signal that is delayed with respect to the analog signal;
• a phase interpolator configured to output, based on a phase compensation code signal and a reference clock signal, a clock signal;
• an analog-to-digital converter group configured to:
• output, based on the analog signal and the clock signal, a plurality of digital samples comprising a first digital sample with a first value, a second digital sample with a second value and a third digital sample with a third value, and
• output, based on the analog signal and the delayed analog signal, a slope type determination signal indicating a rising slope or a falling slope of the analog signal;
• and
• a clock data restorer configured to:
• determine, based on the plurality of digital samples, a curve type indicating a convex curve or a concave curve of a curve comprising the plurality of digital samples,
• obtain, based on the curve type and the slope type determination signal, an evaluation result with respect to a timing of the clock signal, and
• output, based on the evaluation result, the phase compensation code signal,
• wherein, in an eye diagram of the analog signal, the curve type indicates the convex curve based on an open shape of the analog signal being convex and indicates the concave curve based on the open shape of the analog signal being concave, and
• wherein the clock signal is configured to sample the open shape of the eye diagram.