A method and apparatus for resolving time base-generated errors from sampling scope-based measurements. Mutually synchronized repetitive waveform-to-be-analyzed signals (WAS) and repetitive sinusoidal reference signals (RS) are respectively applied to a first channel and a second channel of a sampling scope. A time base generator applies a sampling signal to the first and second channels. An average sine wave period Tav for k samples of RS is determined, followed by determination of phase error φk for each of the k samples, corresponding to phase differences between an ideal sine wave signal and the applied reference sinusoidal signal. Time base error values dk for k samples are calculated from dk=φk*Tav/2π. Error values dk correct time base errors in the sampling signal, and the WAS is re-sampled at sampling times adjusted by dk.