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Simulating power supply spurs in a VCO (Read 3733 times)

sjrg1980 New Member Offline Posts: 1	Simulating power supply spurs in a VCO Feb 01^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.
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wave3x Junior Member Offline Posts: 10 Shang Hai, China.	Re: Simulating power supply spurs in a VCO Reply #1 - Mar 4^th, 2006, 8:07am I am also interesting in this topic, Anyone give me some suggestion?
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Geoffrey_Coram

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Posts: 1999
Massachusetts, USA

Re: Simulating power supply spurs in a VCO
Reply #2 - 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.

If at first you do succeed, STOP, raise your standards, and stop wasting your time.

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Ken Kundert Global Moderator Offline Posts: 2386 Silicon Valley	Re: Simulating power supply spurs in a VCO Reply #3 - 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
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