Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

Simulating VCO Pulling in Cadence

Status
Not open for further replies.
V

venn_ng

Member level 5
Joined
Mar 26, 2017
Messages
87
Helped
1
Reputation
2
Reaction score
1
Trophy points
18
Activity points
645
Is there a way to simulate VCOs pulling on cadence (not injection locking but more like pulling). I want to see the effect of mutual coupling between two LC VCOs. PSS doesnt' seem to converge even with tstab > beat period. Should I run transient only in that case?
 

PSS or HB will converge if you set-up the parameters.I don't know which process you use but convergence is not depended parameters only.
There are other side effects to be considered such as circuit topology,models etc.Pulling analysis is relatively simple in Cadence ADE with Spectre.Change the load resistance and observe the VCO frequency.
Can you post your circuit here ??
 

Hi BigBoss,

I don't know what you mean by changing the load resistance, all I am trying to do is see the effect of pulling between two LC VCOs shown below as I change the mutual coupling factor 'k'.

The problem is when the two LC tanks have different resonant frequencies, the pss is not able to converge for pulling case when k is very small (but not zero).
 

Attachments

  • lc_coupling.png
    lc_coupling.png
    18.7 KB · Views: 141

If there 2 oscillators in the simulation schematic, PSS cannot converge because it cannot decide which oscillator generate fundamental oscillator frequency.And they are also not correlated signals ..
You should simplify the simulation setup.You can couple 2nd tank circuit with appropriate load (R) then you change the coupling factor and observe frequency deviation against coupling factor.
It will give you an insight ( even perhaps not exact ) about Pulling sensitivity of single oscillator.
 

Hi Big Boss,

Thanks for the reply. How about running a transient simulation for the above setup? Would that be accurate?
 

venn_ng said:
Hi Big Boss,

Thanks for the reply. How about running a transient simulation for the above setup? Would that be accurate?
Click to expand...
No, transient analysis would not work.Because you cannot check the frequency deviation due to loading effect.
It may work-maybe-one single value of k but it will not be accurate..
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top