Question about pnoise simulation in cadence:

[mohamedabouzied]

cadence pnoise simulation

Hello all
When i do pnoise of a charge pump of a pll,

the output is dBc/Hz
so, it is normalized to the carrier, right?
What is the carrier here?

i understand this simulation for oscillators as there is a sinsoid carrier i normalized w.r.t. it but for charge pump what is the carrier???????

MohamedAbouzied

 

[safwatonline]

i guess the reference frequency

 

[mohamedabouzied]

hello safwat,
i also gussed this but the carrier is voltage or current??

it seems to be current, am i right??

 

[safwatonline]

ok, let me tell u what i can remember, u should measure the current noise of the CP then multiply it by some factor alpha representing the period that the CP will be ON during lock, then multiply the result current noise by the Transfer function of the current to the output phase, then u calculate the phase noise from L(fm)=theta^2(fm)/2.
that is what i could remember
a good paper to refer to is: https://www.designers-guide.org/Analysis/PLLnoise+jitter.pdf