Apparatus and associated systems, methods and computer program products relate to isolating horizontal jitter component(s) from vertical jitter component(s). In preferred embodiments, at least one horizontal component of jitter is distinguished from at least one component of vertical jitter by fitting a curve to a digitally acquired waveform, determining the curve slope and statistical variance about the fitted curve over at least one time period, identifying a functional relationship between the variance and slope, and determining therefrom at least one horizontal component of jitter and at least one vertical component of jitter. Random and deterministic jitter components may be aggregated, in certain embodiments, so as to identify a vertical jitter component that reflects both deterministic and random jitter. In preferred implementations, the isolated vertical jitter component is subtracted from a total jitter measurement so as to better approximate actual signal jitter.