Jitter can be described as the periodic change of edge period or phase of adjacent pulse edge or even non-adjacent pulse edge. These indicators are suitable for measuring long-term and short-term clock and data stability.The data transmission performance of complex system is predicted by analyzing the jitter index and using the jitter test results.
Periodic jitter is used to measure edge - to - edge timing of clock or data cycle samples. For example, by measuring the time between the rising edges of 1,000 clock cycles, you can sample the statistical cycles that will tell you the quality of the signal.The standard deviation becomes RMS periodic jitter, the maximum period minus the minimum period, to get peak to peak period jitter.The precision of each measurement period determines the precision of jitter measurement.
Phase jitter is used to measure the time deviation between the edge of the measured signal and the edge of a reference signal so that any change in the signal phase can be detected.This indicator is different from periodic measurement in many ways. First, it USES each edge alone, without saying "period" or "cycle."Second, it can measure large time shifts.The edge phase can be deviated by hundreds or thousands of degrees, but can still be measured with very high precision (360 degrees equals one cycle or cycle time). The commonly used measure of phase error is the time interval error (TIE), and the measurement results are expressed in seconds relative to degrees.TIE matches the signal edges to the reference edges, and sums up the differences between the edges.After comparing a large number of edges, a sample set can be provided for analysis.As with the above periodic measurements, the standard deviation becomes RMS TIE, the maximum time minus the minimum time to get peak to peak TIE and so on.