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Monte Carlo simulation of noise contributions using SpectreMDL

svcher

Hello,

I'd like to obtain values of noise contributions in the circuit for each Monte Carlo run.

I was able to make Spectre output total noise for each Monte Carlo iteration into a file, but no luck with noise contributions.

Below is a made-up example: two resistors in series and I am simulating voltage noise at the point where the resistors meet.  Obviously, both resistors contribute to noise.  The example shows how to dump the total noise at each Monte Carlo iteration into a file called "scalars".  Is there a way to make Spectre output noise contributions from r1 and r2 into the same file?

Thanks!

test.scs:
====================================================
r1 (1 0) res_model l=10e-6 w=2e-6
r2 (2 1) res_model l=15e-6 w=2e-6
vr (2 0) vsource dc=1.0 mag=1
model res_model resistor rsh=100 kf=1e-20*exp(dkf)
parameters dkf=0
statistics {
  process {
    vary dkf dist=gauss std=0.5
  }
}
noi (1 0) noise freq=1
====================================================

test.mdl:
====================================================
alias measurement noi_test {
  run noi;
  export real noi_total=noi_test:out;
}
run montecarlo(numruns=10,variations='all,scalarfile="scalars") {
  run noi_test;
}
====================================================

Launch command:  spectre =mdl test.mdl test.scs

Spectre version: 17.1.0.238.isr4

Parents

  • Here's how:

    alias measurement noi_test {
  run noi;
  export real noi_total=noi_test:out;
  export real r1_total=r1:total;
  export real r1_flicker=r1:fn;
  export real r1_thermal=r1:rn;
  export real r2_total=r2:total;
  export real r2_flicker=r2:fn;
  export real r2_thermal=r2:rn;
}
run montecarlo(numruns=10,variations='all,scalarfile="scalars") {
  run noi_test;
}

    The easiest way to check the contribution names for each device is to run just "spectre test.scs" and then look in the results browser in ViVA. Obviously in this case the thermal noise doesn't vary within the Monte Carlo, but the flicker noise does (and so the total does too).

    Regards,

    Andrew.

  • in reply to Andrew Beckett

    Thank you Andrew, this answers my question.

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