VCO Loop gain simulation

[Eric]

Hi,

is there application note or an explanation on how can we measure
VCO's loop gain using the CMDMProbe?

B.R

 

[Mobil]

On Jun 27, 6:52 pm, Eric <arik...@gmail.com> wrote:

Hi,

is there application note or an explanation on how can we measure
VCO's loop gain using the CMDMProbe?

B.R

I'm thinking of that using a port to measure the negative resistance
(like real(Z)) would be simple.

 

[Andrew Beckett]

Eric wrote, on 06/27/10 09:52:

Hi,

is there application note or an explanation on how can we measure
VCO's loop gain using the CMDMProbe?

B.R

Look in
<MMSIMinstDir>/tools/spectre/examples/SpectreRF_workshop/SpectreRF_AN/PstbAN.pdf

This talks about using pstb versus stb for stability analysis of a VCO. Using
cmdmprobe for differential stability (rather than single-ended stability) is no
different than from non-periodic analyses. You can only use it for balanced
loops (i.e. no significant CM->DM or DM->CM leakage) and it can measure either
common-mode or differential-mode stability based on a parameter on the cmdmprobe
instance (there's a solution on Cadence Online Support for this, I'm sure).

Regards,

Andrew.