Even-Odd (F/2) Result

Click F/2 on the Measurement (Meas) toolbar to activate Jitter mode's F/2 jitter (J_(F/2)) measurement, also known as even-odd jitter (J_(even-odd). F/2 occurs as the result of timing data with a half-rate clock. If the clock is asymmetric then even symbols versus odd symbols will differ in length from nominal.

The following figure shows an eye diagram in which blue and orange colors identify the portions of an eye that are created with the signal's even or odd symbols. This is one signal; the colors do not represent different scope channels. The eyes, formed by the even and odd symbol periods, are overlaid on top of each other with example symbol periods of 90 ps and 110 ps.

F/2 jitter is the measure of the difference in edge positions of even/odd symbols. In the figure, F/2 jitter directly measures the difference in the edge positions identified by dotted lines in the figure, which in this case is 10 ps of F/2 jitter.

This measurement is only available in Jitter Mode. When measuring a simulated waveform, the pattern length in pattern lock setup must be set to an even number by doubling the pattern length setting in the simulator. On real signals, you must assure that the pattern is consistent with any measurement standard requirements.

More Information

• Jitter Components Tree
• Measurement Toolbar

SCPI Command

:MEASure:JITTer:FOVer2