Jitter measurement for VCO

Hello Folks!

I have designed a Voltage coltrolled oscillator (VCO), and would like to measure the jitter it produces at the output.

From the output swing, I note that the VCO has a free running frequency of say, ´f´.

For this, I have run a transient analysis (say for 10 ns) and then plotted the output voltage vs time.

I go to Measurements -> Eye diagram

I have given the following inputs:

      Start time: 0,

      Stop: 10 ns,

      Unit Interval: 1/(2f)

Please note that I have a proper eye opening only at a bit interval of 1/(2f), not at 1/f.

I click on Eye measurements tab at the bottom and select the eye.

I have given the threshold as half of the eye height, and then click on Evaluate button at the bottom.

I get a list of values that includes Random JItter (left and right) and deterministic jitter. I am adding them for the total jitter.

Is this the correct approach for jitter measurement?

Regards,

Tuka