Hi nadroit,
If you cannot access cadence online help, generate eye diagram of the VCO output and measure it with delta cursors.
![Smiley Smiley](https://designers-guide.org/forum/Templates/Forum/default/smiley.gif)
If you can access cadence online help, please have a look at solution # 11395772, 11018920, and 11564054. Or have a look at the following link.
http://www.designers-guide.org/Forum/YaBB.pl?num=1293197122/0#0BTW, I am not sure whether the solution in the above 3 solutions are all compatible with your product version, IC51.
Best Regards,
Yawei