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Uncorrelated Noise for Ports

illaoi

Hi,

I wanted to do phased array front-end simulation and needed Mutiple ports with uncorrelated noise, however in my tran noise sim, I see the difference between two nets are zero which means they have the same noise which is not the case in phased array systems. Any suggestion to address this issue?

Thanks

Parents

  • I didn't believe this, so I just tried it and don't see this behaviour (I can't really see how the noise of the two nodes - I assume you mean the top end of each resistor - can be the same). Are you sure you've actually enabled transient noise?

    What does your input.scs look like?

    Here's my test (a handwritten netlist, but should be similar):

    //

    port0 (n1 0) port
    r0 (n1 0) resistor r=50

    port1 (n2 0) port
    r1 (n2 0) resistor r=50

    tran tran stop=1u noisefmax=1G

    and here's the results - the top two traces are n1 and n2, and the bottom is the difference:

    Andrew

  • in reply to Andrew Beckett

    Andrew,

    Thanks, here is input.scs, but you are right, I probably made a mistake on plotting, now it works as expected.

    R1 (net2 0) resistor r=50
    R0 (net1 0) resistor r=50
    PORT1 (net2 0) port r=50 type=sine freq=frf dbm=prf
    PORT0 (net1 0) port r=50 type=sine freq=frf dbm=prf isnoisy=yes
    simulatorOptions options psfversion="1.4.0" reltol=1e-3 vabstol=1e-6 \
    iabstol=1e-12 temp=27 tnom=27 homotopy=dptran scalem=1.0 scale=1.0 \
    gmin=1e-12 rforce=1 maxnotes=5 maxwarns=5 digits=5 cols=80 pivrel=1e-3 \
    sensfile="../psf/sens.output" checklimitdest=psf fixdanglingnodes=1 \
    fixtopologyresistor=1e10
    tran tran stop=160.08n errpreset=liberal noisefmax=30G noiseseed=1 \
    psdplotparams=[40p 160.04n 16 3 25G] write="spectre.ic" \
    writefinal="spectre.fc" annotate=status maxiters=5

Reply
  • in reply to Andrew Beckett

    Andrew,

    Thanks, here is input.scs, but you are right, I probably made a mistake on plotting, now it works as expected.

    R1 (net2 0) resistor r=50
    R0 (net1 0) resistor r=50
    PORT1 (net2 0) port r=50 type=sine freq=frf dbm=prf
    PORT0 (net1 0) port r=50 type=sine freq=frf dbm=prf isnoisy=yes
    simulatorOptions options psfversion="1.4.0" reltol=1e-3 vabstol=1e-6 \
    iabstol=1e-12 temp=27 tnom=27 homotopy=dptran scalem=1.0 scale=1.0 \
    gmin=1e-12 rforce=1 maxnotes=5 maxwarns=5 digits=5 cols=80 pivrel=1e-3 \
    sensfile="../psf/sens.output" checklimitdest=psf fixdanglingnodes=1 \
    fixtopologyresistor=1e10
    tran tran stop=160.08n errpreset=liberal noisefmax=30G noiseseed=1 \
    psdplotparams=[40p 160.04n 16 3 25G] write="spectre.ic" \
    writefinal="spectre.fc" annotate=status maxiters=5

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