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https://designers-guide.org/forum/YaBB.pl Measurements >> Phase Noise and Jitter Measurements >> jitter simulation with Virtuoso SpectreRF v.5.1.41 https://designers-guide.org/forum/YaBB.pl?num=1169808872 Message started by LucaV on Jan 26th, 2007, 2:54am |
Title: jitter simulation with Virtuoso SpectreRF v.5.1.41 Post by LucaV on Jan 26th, 2007, 2:54am Hi I'm tring to calculate the jitter introduced by an ideal VCO driven by a noisy resistor (thermal noise). from literature and theory I expect Phase noise: 2*k*t*R*Kf^2 | where : k -> bolthzman's L(f)=---------------------- | t -> temperature [kelvin] f^2 | R -> resistance Kf -> gain of the VCO from this equation I get a result that match exactly with Cadence simulation done with Virtuoso SpectreRF v.5.1.41. Virtuoso SpectreRF v.5.1.41 gave a new function in the pnoise tool: jitter noise type. from the Ken Kundert's "Predicting the PN and J pf PLL frequency Synthesizers" and other papers in literature I expect a jitter: ____________ _______________ | f^2 | 2*k*t*Kf^2 J= | L(f)* -------- = | ------------------ \| f0^3 \| f0^2 My problem is that jitter prediction based on this theory doesn't macth with cadence result (completely wrong order of magnitude) and I don't know why!! |
Title: Re: jitter simulation with Virtuoso SpectreRF v.5. Post by neoflash on Jan 26th, 2007, 11:00pm The equation on jitter, given there, is not rms jitter. It is spurious jitter i guess. For calculating RMS jitter, you need to refer to Ken's document which is available on this forum. |
Title: Re: jitter simulation with Virtuoso SpectreRF v.5. Post by LucaV on Jan 29th, 2007, 7:15am the jitter's equation that I have used has benn taken from Ken's "predicting the phase noise and jitter of PLL-based frequency synthesizer" pgg.33, equation(80). I don't understand how I can get the rms value: i belive (waching how the equation are obteined) that this expression is already rms. |
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