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 Problems when evaluating waveforms from multiple stb analyses during transient analysis 

Last post Wed, May 29 2013 2:40 AM by Andrew Beckett. 2 replies.
Started by Rune 23 May 2013 01:03 AM. Topic has 2 replies and 800 views
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  • Thu, May 23 2013 1:03 AM

    • Rune
    • Not Ranked
    • Joined on Fri, Jul 16 2010
    • Trondheim, Sor-Trondelag Fylke
    • Posts 4
    • Points 65
    Problems when evaluating waveforms from multiple stb analyses during transient analysis Reply
    I face some problems in adexl with transient and stb analysis at two times points using spectre/mmsim 111 isr22 and ic615.16.2.

    I run a transient simulation with ac times(where stb analysis is run): t_stb1 and t_stb2.
    I find the loopgain at the two time points with these expressions in adexl:
    ymax(dB20(famValue(getData("loopGain" ?result "stb") VAR("t_stb1"))))
    ymax(dB20(famValue(getData("loopGain" ?result "stb") VAR("t_stb2"))))

    This works for one adexl testbench but not for two others. In latter case, the loop gain for the last time point is evaluated in both cases. Looking at the loopgain waveforms, I see that the waveforms have a "sweep parameter" t_stb2 (which explains why this occurs). 

    Is there another way to have this correct regardless of what kind of parameters that are for some reason included in the waveform?

    • Post Points: 5
  • Mon, May 27 2013 12:04 PM

    • Rune
    • Not Ranked
    • Joined on Fri, Jul 16 2010
    • Trondheim, Sor-Trondelag Fylke
    • Posts 4
    • Points 65
    Re: Problems when evaluating waveforms from multiple stb analyses during transient analysis Reply

    A follow up to this problem. 

    This seems to occur with many types of analyses. However, one workaround is to find the sweep parameter name(which, in my case, seems to be an arbitrary variable from the global variables list), and then get the corresponding value. Like this:

    ymax(dB20(mag(famValue(value(v("/INT_AC_LP_DIFF" ?result "ac") famGetSweepName(v("/INT_AC_LP_DIFF" ?result "ac")) famGetSweepValues(v("/INT_AC_LP_DIFF" ?result "ac")))  VAR("t_ac1"))))) 

    • Post Points: 20
  • Wed, May 29 2013 2:40 AM

    Re: Problems when evaluating waveforms from multiple stb analyses during transient analysis Reply

    Rune,

    For me, if I use:

    ymax(value(db(mag(getData("loopGain" ?result "stb"))) 'time VAR("tstb1")))

    Then it always works (similarly if I use tstb2 for my second time point. I'm using IC615 ISR16 (6.1.5.500.16.2). However, I do see issues if I just try to have an output:

    value(db(mag(getData("loopGain" ?result "stb"))) 'time VAR("tstb1"))

    then that fails to plot. If I explicitly put the time in there rather than the VAR expression, it works - and I see the additional sweep in the results. Something is definitely wrong here, so I'll file a CCR. I've seen a few similar issues recently.

    Regards,

    Andrew.

    • Post Points: 5
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Started by Rune at 23 May 2013 01:03 AM. Topic has 2 replies.