How is Residual Jitter measured? There are several methods used to measure Jitter. The most common is to recover the clock from the signal with a very low jitter PLL (often VCXO based) and then use this clock to trigger an oscilloscope which has the received signal connected to it's input. The scope will display an eye diagram, and plotting a histogram about the crossing point will allow you to get a measure of the jitter. Most systems look at the RMS jitter, which is usually the measure that the 'scope will give you.