Analyzing Jitter

“Jitter Analysis” delves into the advanced capabilities and benefits of jitter analysis, a crucial feature for ensuring signal integrity in the next-generation Infiniium EXR, MXR, and UXR-series oscilloscopes.

The lesson begins by introducing jitter analysis as a consolidated option that combines three previously separate features into one package. The first iteration of this comprehensive jitter analysis software, EZJIT, is located under the “Analyze - Measurement Analysis” menu. Although initially developed for jitter analysis, users found it useful for examining the histogram, trend, and spectrum of any measurement, not just those related to jitter.

To illustrate its application, the lesson uses a clock signal and adds a clock-focused time interval error measurement for analysis. Enabling the histogram reveals a bimodal distribution and the trend confirms a predominantly sinusoidal jitter profile. The spectrum feature helps visualize the frequency content of the trend, which is particularly useful for more complex trends.

The lesson demonstrates how a frequency-modulated burst can be effectively demodulated by trending a frequency measurement on the screen, showing the linear ramp of frequency across the burst. While measurement histograms, trends, and spectrums can be set up manually without purchasing the jitter analysis option, the video emphasizes the convenience and added value of the EZJIT Plus and EZJIT Complete features, as well as the phase noise analysis included in the package.

EZJIT Plus is designed for random jitter and deterministic jitter analysis, as well as other jitter decomposition measurements. EZJIT Complete, an add-on, includes the decomposition of vertical noise, providing a complete statistical analysis of the signal. Both tools are located under the “Analyze - Jitter / Noise” menu, with a setup wizard and a quick setup option. The quick setup configures clock recovery methods and thresholds and enables fundamental timing jitter plots and measurements.

The lesson highlights EZJIT Complete's phase noise measurement feature. This feature uses a two-channel cross-correlation technique to lower the oscilloscope’s phase noise measurement floor by splitting the clock source signal into two oscilloscope input channels. The wizard is recommended for guiding users through the process in a simplified, step-by-step manner.

Decomposing jitter and noise into subcomponents provides valuable diagnostic information about the signal and a method to estimate total jitter and total interference at bit error rate levels that would be too low to measure directly.