I am designing an injection locked vco. My simulation scenario for the phase noise is as follows:
1. Run the vco without the injection signal for 2 microseconds ; let it setttle to the free running frequency;
2. Start the injection signal and observe the phase noise...
Well, I need a periodic vsine source to generate the injection signal in the schematic; and this is the very source of an error in my pss simulation:
" 'V0' is a periodic input signal, which is inconsistent with autonomous circuits. "
this is what happens if I set cadence for phase noise simulation using the instructions given in the cadence Spectre manual.
I know... the instructions are for a 'normal' vco; but I was hoping that it would work for my injection locking case as well.
Question, as obvious it is by now :), how do we simulate the injection locked oscillator phase noise ?
Is there a way to conceal the periodic voltage source in the circuit so as not to piss the pss off ?
Hi Calp, If you have access to Cadence Online Support website then there is a solution on how to simulate such vco – http://support.cadence.com/wps/mypoc/cos?uri=deeplinkmin:ViewSolution;solutionNumber=11182082
For such oscillators you shouldn’t be using the Oscillator button in the PSS form as this is considered a driven circuit since it is driven by an injection source. That is the reason you are receiving the error message. Once you set the PSS form accordingly, set the tstab to 100 periods (and can also use the saveinit button to save the initial transient waveform before steady state). You should now be able to run the simulation. With Regards,Ashish
thanks ashish.. looks like we are getting somewhere. :)
Unfortunately, I don't have access to the link. Would you mind telling me more abt the pss/pnoise setup for these driven cct cases?
vco free running freq : 106 MHz.
injection freq: 111MHz.
Please login to http://support.cadence.com and do a search on 11182082 . That should take you to the solution that Ashish is referring to:
I just verified this myself.