System jitter is the overall jitter due to power supply noise, board noise, or any extra jitter of the system.
Use the set_system_jitter command to set only one value for the whole
design, that is, all the clocks.
The following command sets a +/-100 ps jitter on the primary clock propagating through
input port clkin:
set_input_jitter [get_clocks -of_objects [get_ports clkin]] 0.1Note: The impact of input jitter and system jitter in the
overall calculation of the clock uncertainty is not trivial and does not follow a single
equation. The calculation of the clock uncertainty is path-dependent and depends on the
clocking topology, the clock-pair involved in the path, the presence or not of an
MMCM/PLL on the clock tree, and other considerations. However, the text and GUI of the
Report Timing command expose the breakdown of the clock uncertainty for each timing
path.