A method of determining jitter is provided by providing a sample, performing an unwrap of the data and then performing a Fast Fourier Transform (FFT) of the data. The fundamental is filtered out and an inverst FFT is determined. The sparkle code is taken out and the phase is adjusted to a known phase. The noise difference at both the high and low rtates by angles is determined. The jitter by angle is calculated using the high slew variance and low slew variance. The average jitter is then calculated.