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https://designers-guide.org/forum/YaBB.pl Simulators >> RF Simulators >> jitter measurement from spectre pnoise https://designers-guide.org/forum/YaBB.pl?num=1273877534 Message started by nisha on May 14th, 2010, 3:52pm |
Title: jitter measurement from spectre pnoise Post by nisha on May 14th, 2010, 3:52pm Hi, Let me mention first of all that I haven't used spectre since school so please forgive dumb questions! I'm trying to measure the jitter on a ring oscillator using spectre's pnoise analysis. (1) When I try to select noisetype "pmjitter" and run pnoise analysis, I get the error: Internal error found in spectre at freq = 200 MHz during PNoise analysis `pnoise'. Please run `getSpectreFiles' or send the netlist, the spectre log file, the behavioral model files, and any other information that can help identify the problem to support@cadence.com. FATAL (CMI-2007): Error detected in file `dfiOut.c' at line 3037. FATAL (SPECTRE-21): Assertion failed. In the first place, I had a tough time getting pss to converge, which wasn't the case when I selected noisetype "sources". The fundamental frequency is being calculated correctly. Parameters used: sweeptype=relative relative harmonic=1 threshold=0.75 (the swing of the vco is 0.5 to 1V) crossing direction=rise noisetype=pmjitter maximum sideband=15 tolerance=1e-10 For pss, tstab=100.6n method=gear2only steadyratio=0.1 I tried giving an initial condition as well. 2) can I calculate the jitter from the phasenoise plot with noisetype=sources? I'm trying to use expression 16 and the spreadsheet from this appnote: http://www.maxim-ic.com/app-notes/index.mvp/id/3359 But the jitter number seems very high and urealistic. What am I missing? 3) How do I calculate rms accumulated jitter from the phase noise plot? Would deeply appreciate any insight into this! Thanks in advance! |
Title: Re: jitter measurement from spectre pnoise Post by nisha on May 19th, 2010, 12:28am Sorry for posting this in the wrong board, I'm not sure how to move it now. I got answers to (2) and (3) from other posts and Ken's paper, but if anyone has any ideas about (1), please let me know! Thanks! |
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