Emre
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Posts: 10
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I designed a frequncy detector (frequency-to-voltage converter), but it has ripples on the output voltage and after the filter this result in some fluctiations at the input of the VCO, so the VCO output frequency doesn't settle at one frequency, but have perodic ripples on it. When I run pss on the system, pss doesn't converge.
I changed several parameters that are written in SpectreRF documentation and at the end find out that increasing steadyratio upto 10 help it to converge. However; this time simulator gives a warning that pss analysis may be insufficiently accurate for pnoise analysis and The Floquet eigenspace computed by PSS appears to be inaccurate, so PNOISE can be inaccurate and asks me to run with smallet reltol.
Then I modeled the VCO in voltage domain with jitter as it's described in Kenn's paper and the codes in this webpage. After fixing the hidden state problem, when I run PSS and PNOISE again, I realized the same problem and after increasing the steadyratio, I couldn't get any phase noise, even if there is quite a lot jitter.
Two problems can be because of the same reason and if it's what is the best way to handle these kind of situations in SpectreRF.
Emre
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