1. A method of measuring a parameter of a signal under test in an integrated circuit, comprising: providing the integrated circuit that generates the periodic signal, wherein the periodic signal has a frequency; generating from within the integrated circuit a time-base signal having the frequency of the periodic signal and a variable delay relative to the periodic signal; performing a test that includes sampling, with a one-bit sampler over a number N of cycles of the time-base signal, the periodic signal in response to the time-base signal a plurality of times each having a differing value of the variable delay; and for each of the plurality of times, counting over the N cycles the number of sampled occurrences of a particular bit value captured by the one-bit sampler.