I need to calculate the peak to peak jitter, Absolute and Cycle to cycle jitter of a VCO output in cadence spectre.. has any one done this before or any ideas.
I am able to setup a calculator variable and sweep the edge number and plot graph of the crossover points vs edge number..... but i cannot get graph to be saved as CSV for post processing... does any body know where cadence saves the calculated variables. I cannot find it in the result browser...
two ways:
1. Inject the noise into supply, and measure the vco cycle time, then do statistical analysis
2. Do Pnoise analysis then integrate between frequency range
i think there is another way for you to measure jitter by plotting eyediagram of the signal.
in the ADE window, setup-->Enviroment Options, in the Enviroment Options dialogue box, fill in userCmdLineOption with -format psfbin, click OK to save, then run transient analysis in spectre. after finishing simulation, use cscope to open the result file, it's very convenient to plot eyediagram in cscope, then you can measure jitter.
To get a result you need good inputs. I have simulated jitter many
times by imposing a voltage noise on signals, you can now do this
with tnoise as well, but the question is, what -is- the noise?