# DDJ vs Symbol

The graph of Data-Dependent Jitter (DDJ) versus relative symbol position shows relative symbol position on the horizontal axis. The vertical axis indicates negative (-) time for samples that occur earlier than expected and positive (+) time for samples that occur later than expected.

The symbol numbers displayed on the horizontal axis are relative values only and may change each time the logical bit pattern of the source waveform is recalculated.

A blue dot on the graph marks the earliest arriving edge. This is the relative symbol position that measured the greatest magnitude negative jitter value. A red dot on the graph marks the latest arriving edge. This is the relative symbol position that measured the greatest magnitude positive jitter value. The time span between the earliest and latest arriving edges is reported as the value of DDJ (p-p) in the results table.