calculation of VCO output power in cadence spectre

Status
Not open for further replies.

ddis

Member level 2
Joined
Jun 30, 2011
Messages
42
Helped
3
Reputation
6
Reaction score
3
Trophy points
1,288
Activity points
1,534
Hi all,

i have to calculate the output power of VCO in cadence spectre. i am using pss & pnoise analysis. Actually the Collpitts I/Q VCO (4.8Ghz) is designed by another person.
I just know its specs. Its o/p swing is +0.75V to -0.75V. After doing the analysis i go to Results>Direct Plot>Main Form
it asks for the resistance value

Now i have a doubt here. The VCOs o/p is going to frequency divider so the output will see a capacitive load with a small resistance. So what value of resistance to use while calculating the output power.

I have attached the screenshot
 

I've got the same question but I'm designing a ring VCO so I have no resistance at the output except for small signal (ro)
 

I've also got this problem during design a cross-coupled VCO, if u know how to do it, plz tell me
 

Status
Not open for further replies.
Cookies are required to use this site. You must accept them to continue using the site. Learn more…