Methods and circuits for measuring clock phase uniformity of multi-phase clock set, including by generating at least one DC phase difference signal such that the DC phase difference signal is, or the DC phase difference signals are, indicative of the phase difference between the clocks of each of multiple pairs of clocks of the clock set, and methods and circuitry for generating such DC phase difference signals. Preferably, multiplexer circuitry asserts to DC signal generation circuitry any selected one of a number of pairs of clocks of the clock set, and the DC signal generation circuitry includes logic (for generating a binary signal in response to each clock pair) and a low pass filter for generating a DC phase difference signal in response to the binary signal. Other aspects are receivers and transmitters that include circuitry for generating at least one DC phase difference signal, and systems including at least one such transmitter (or receiver) and a link (e.g., a multi-channel or single-channel serial link) coupled thereto.