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https://designers-guide.org/forum/YaBB.pl Measurements >> Phase Noise and Jitter Measurements >> Cadence IC5.1 and MMSIM10.1 https://designers-guide.org/forum/YaBB.pl?num=1440012769 Message started by Naga Kishan on Aug 19th, 2015, 12:32pm |
Title: Cadence IC5.1 and MMSIM10.1 Post by Naga Kishan on Aug 19th, 2015, 12:32pm Hi, I am using Cadence IC5.1 with MMSIM10.1 and simulating for phase noise using PSS/Pnoise analysis. The simulation runs well for PSS, but it shows 2 warnings as shown below for Pnoise: 1) Warning from spectre at freq = 100 MHz during PNoise analysis `pnoise'. WARNING (SPECTRE-16518): Arithmetic exception in analysis `pnoise' . .. 2) Warning from spectre at freq = 1 Hz during PNoise analysis `pnoise'. WARNING (SPCRTRF-15037): Infinite flicker noise is ignored. I will be obliged for your help. Regards, Naga |
Title: Re: Cadence IC5.1 and MMSIM10.1 Post by Naga Kishan on Aug 20th, 2015, 1:22pm Hi, I am using the following specifications to calculate the CMOS ring oscillator (Inverter-5stage) PSS Engine: Shooting Fundamental frequency 3.1GHz Number of Harmonics 64 errpreset: moderate tstab: 333ns Oscillator . clk, gnd! pnoise sweeptype. relative relative harmonic: 1 output frequency sweep range: 100K - 100MHz sweep type: log points per decade: 200 Maximum sidebands - 64 output - voltage - clk, gnd! Noise type - sources Noise separation - yes I get the below attached phase noise value. So, my main questions are: 1. Does this plot look reasonable? 2. what should be the phase noise value for a best ring oscillator (or in a range of dBc/Hz) 3. It is used for a divider circuit which CML logic which uses differential clocks ( clk and clkb ), so i designed with a inverter at the output of the oscillator. So, my question is does the phase noise differ for clk and clkbar (complement). does i need to use clkb for reference node in both pss as well as pnoise. Thanks for your quick reply in advance. |
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