Is this setup for pss/pnoise correct?

[zhangljz]

Hello,

I want to simulate the PLL phase noise with pss/pnoise, but it always doesn't converge.
I am not sure if my setup is correct,. Anybody can help to check?

The input reference frequency is 10MHz, output frequency is 80MHz. And I use a 'vpulse' to generate the reference clock.

So here is my setup. I want to see the phase noise of 'vco_p<1>', which is the output of VCO.



Thanks a lot

 

[jdp721]

Try out by checking the "oscillator" option in your PSS settings.

Refer internet resources like https://www.lumerink.com/courses/ECE518/Handouts/VCO_PSS.pdf

 

[zhangljz]

Hi,

I use a 'vpulse' as the reference clock source. Since pll is a driven circuit, so I can't check the 'oscillator' option.

I am wondering if it is possible to calculate the phase noise with the pll transient simulation result in matlab. Anybody knows?


Thank you.

 

[BigBoss]

Hi,

I use a 'vpulse' as the reference clock source. Since pll is a driven circuit, so I can't check the 'oscillator' option.

I am wondering if it is possible to calculate the phase noise with the pll transient simulation result in matlab. Anybody knows?


Thank you.

You cannot simulate whole PLL with PSS and it's not possible to find Phase Noise of a PLL by doing ordinary simulations ( PSS,Transient etc.).Because PLL is a closed loop and therefore its structure is not suitable for those kind of simulations.
You may simulate VCO standalone by doing PSS+PNOISE then you should treat that information in a "System Simulator" to reproduce a model of your PLL.There are some approximations to do this and you'd better study on it more..

 

[vfone]

https://literature.cdn.keysight.com/litweb/pdf/5989-9471EN.pdf