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purpose of file "sp.noise.sp"

Ymmen

Hi,

During SP analysis of LNA circuit (quite large netlist due to extracted views), the simulation is very slow. I could trace it to a file (sp.noise.sp) in psf folder, which I believe gets written after SP calculation at every frequency and hence gets very large in size(~2GB). What is the purpose of this file? Does it write noise summary of each instance in that file? If I want to simulate only noise figure and not care about noise summary, how can I avoid writing to such a file, and hence speed up my SP analysis?

SP stands for S parameter.

Thanks 

Parents

  • Firstly this is because you have the "Do Noise" checked on the sp analysis form - it then performs a noise analysis as part of the s-parameter analysis, and writes the output data into the sp.noise.sp database. It also outputs any noise contributions from each component into this database as well (these can then be shown via Results->Print->Noise Summary. 

    If you don't want to analyse noise, you can simply turn off the "Do Noise" (set it to "no"). If you want to analyses noise, but don't want the contributions, then right now the only way to do that is via the Outputs->Save All form and to set "Signals to output (save)" at the top to "lvlpub" and the "Select level of subcircuit to output (nestlvl)" to 0. You can't currently do this on the sp analysis specifically, so this will impact all analyses - so if you were running transient at the same time, that would limit the signals saved there too. I filed an enhancement change request (CCR 2212787) to allow save/nestlvl to be specified on the sp analysis directly (the noise analysis already supports this). Turning off the noise contributions should make a massive reduction in the file size as then only a few waveforms are saved.

    Regards,

    Andrew.

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