Patent ID: 7174279

Claim:
A method of performing a measurement on a differential signal, comprising: a) providing each leg of the differential signal to an input of a comparator having at least a first and second input; b) introducing a plurality of bias levels into the comparison, whereby the output of the comparator has a logical value representative of a value at the first input compared to a value at the second input offset by the bias level; c) taking a plurality of sets of samples of the output of the comparator, with a set of samples for each of the bias levels, each of the samples in each of the sets correlated in time to a point on the waveform; d) selecting a set of samples based on the percentage of samples in the set having a first logical value; and e) associating the bias value used to take the samples in the selected set with the value of the differential signal at the point on the waveform.