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Simulators >> RF Simulators >> Simulating power supply spurs in a VCO
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Message started by sjrg1980 on Feb 1^st, 2006, 3:06pm

Title: Simulating power supply spurs in a VCO
Post by sjrg1980 on Feb 1^st, 2006, 3:06pm

Hello people,
I am trying to simulate the effect of power supply spurs and noise on the phase noise of the VCO. In order to simulate the noise from the power supply I can include a noise file in the power supply in Spectre simulator. That works. How do I simulate the spurs? Can it be simulated just like noise?

Ganesh.

Title: Re: Simulating power supply spurs in a VCO
Post by wave3x on Mar 4^th, 2006, 8:07am

I am also interesting in this topic, Anyone give me some suggestion?

Title: Re: Simulating power supply spurs in a VCO
Post by Geoffrey_Coram on Mar 15^th, 2006, 5:39am

Spurs are fixed-frequency (eg, 60Hz) components to what is supposed to be a dc supply, right?

So, you could put a small amplitude sine source in series with your dc voltage source.

Vdc (extra 0) vsource dc=5.0
Vspur (vdd extra) vsource type=sine freq=60 ampl=1u

where "vdd" is the net where the dc source was originally attached.

Title: Re: Simulating power supply spurs in a VCO
Post by Ken Kundert on Mar 15^th, 2006, 8:44am

You can also apply the unwanted signal that is causing the spur as a small signal and compute the transfer function from where the signal is applied to the output of the oscillator using PSS/PAC or PSS/PXF. This works well if the spur is small.

-Ken