Stats

  • Locked Locked
  • Replies 25
  • Subscribers 63
  • Views 25741
  • Members are here 0
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Using Montecarlo simulation for finding Rise and fall tile of a SETTLING waveform

RFQuery

 Dear All,

I want to do MONTE_CARLO simulation for my circuit for finding rise time and fall time.

The output is settling after 800u s.

I have to do some pre-processing before finding the last expression. The expressions I used as below.

But it did NOT work.

Can anybody tell how to find risetime and falltime of the waveform using MONTE-Carlo simulation if one needs some house-keeping processing of the waveform.

 .......

analysis('dc ?saveOppoint t  )
analysis('tran ?stop "1u"  ?errpreset "moderate"  ?maxstep "5p" 
        ?method "euler"  ?strobeperiod "5p"  )
desVar(      "frf" 6G    )
desVar(      "prf" -20    )
desVar(      "frf2" 6.1G    )
desVar(      "w" 20u    )
desVar(   "sigma" 3)
option(    'temp  "27.0"
    'iabstol  "1e-14"
    'vabstol  "1e-4"
)
saveOption( 'currents "selected" )
saveOption( 'save "all" )
temp( 27.0 )
monteCarlo( ?numIters "1" ?startIter "1"
    ?analysisVariation 'processAndMismatch ?sweptParam "None"
    ?sweptParamVals "27" ?saveData nil
    ?nomRun "yes" ?append nil
    ?saveProcessParams t
)
CLOCK_DUTY_PERIOD=2.5e-10
CLIP_START=0.8u
CLIP_END=0.9u

clip_I_P=clip( v("/MIXER_I_P" ?result 'tran) CLIP_START CLIP_END)
plot(clip_I_P)
MIN_VALUE=ymin(clip_I_P) + 0.02
MAX_VALUE=ymax(clip_I_P)- 0.03
UPPER_THRESOLD=MIN_VALUE + ( (MAX_VALUE-MIN_VALUE)*0.9 )
LOWER_THRESHOLD=MIN_VALUE + ( (MAX_VALUE-MIN_VALUE)*0.1 )
RISE_UPPER= cross( clip_I_P UPPER_THRESOLD 2 'rising )
RISE_LOWER= cross( clip_I_P LOWER_THRESHOLD 2 'rising )

monteExpr("RISE_TIME" "abs(RISE_UPPER-RISE_LOWER)")

monteRun()
Parents

  •  The problem is that the expression is evaluated within the simulator (actually in a process called "artil") which will have no visibility of the calculations you are doing to preprocess the results. So, there are a couple of options:

    First, you might define a function (please check the code below properly, since I didn't test it) and put it in a file called ~/.artilinit :

    procedure(MyRiseTime(signal CLIP_START CLIP_END)
      let((clip_I_P MIN_VALUE MAX_VALUE UPPER_THRESHOLD LOWER_THRESHOLD RISE_UPPER RISE_LOWER)
        clip_I_P=clip( signal CLIP_START CLIP_END)
        MIN_VALUE=ymin(clip_I_P) + 0.02
        MAX_VALUE=ymax(clip_I_P)- 0.03
        UPPER_THRESOLD=MIN_VALUE + ( (MAX_VALUE-MIN_VALUE)*0.9 )
        LOWER_THRESHOLD=MIN_VALUE + ( (MAX_VALUE-MIN_VALUE)*0.1 )
        RISE_UPPER= cross( clip_I_P UPPER_THRESOLD 2 'rising )
        RISE_LOWER= cross( clip_I_P LOWER_THRESHOLD 2 'rising )
        abs(RISE_UPPER-RISE_LOWER)
      )
    )

    then in your OCEAN script, you'd just do:

    CLIP_START=0.8u
    CLIP_END=0.9u
    monteExpr("RISE_TIME" sprintf(nil "MyRiseTime(v(\"/MIXER_I_P\" ?result 'tran) %g %g)" CLIP_START CLIP_END))

    If you're using two old a version where the ~/.artilinit file is not supported, you can instead do:

    CLIP_START=0.8u
    CLIP_END=0.9u
    monteExpr("dummy" "{load(\"/path/to/file/containing/above/function.il\") 1.0})
    monteExpr("RISE_TIME" sprintf(nil "MyRiseTime(v(\"/MIXER_I_P\" ?result 'tran) %g %g)" CLIP_START CLIP_END))

    What that does is load your custom function, but make it look like an expression that returns a number - and then uses it in the second monteExpr.

    Hope that helps,

    Regards,

    Andrew.

Reply

  •  The problem is that the expression is evaluated within the simulator (actually in a process called "artil") which will have no visibility of the calculations you are doing to preprocess the results. So, there are a couple of options:

    First, you might define a function (please check the code below properly, since I didn't test it) and put it in a file called ~/.artilinit :

    procedure(MyRiseTime(signal CLIP_START CLIP_END)
      let((clip_I_P MIN_VALUE MAX_VALUE UPPER_THRESHOLD LOWER_THRESHOLD RISE_UPPER RISE_LOWER)
        clip_I_P=clip( signal CLIP_START CLIP_END)
        MIN_VALUE=ymin(clip_I_P) + 0.02
        MAX_VALUE=ymax(clip_I_P)- 0.03
        UPPER_THRESOLD=MIN_VALUE + ( (MAX_VALUE-MIN_VALUE)*0.9 )
        LOWER_THRESHOLD=MIN_VALUE + ( (MAX_VALUE-MIN_VALUE)*0.1 )
        RISE_UPPER= cross( clip_I_P UPPER_THRESOLD 2 'rising )
        RISE_LOWER= cross( clip_I_P LOWER_THRESHOLD 2 'rising )
        abs(RISE_UPPER-RISE_LOWER)
      )
    )

    then in your OCEAN script, you'd just do:

    CLIP_START=0.8u
    CLIP_END=0.9u
    monteExpr("RISE_TIME" sprintf(nil "MyRiseTime(v(\"/MIXER_I_P\" ?result 'tran) %g %g)" CLIP_START CLIP_END))

    If you're using two old a version where the ~/.artilinit file is not supported, you can instead do:

    CLIP_START=0.8u
    CLIP_END=0.9u
    monteExpr("dummy" "{load(\"/path/to/file/containing/above/function.il\") 1.0})
    monteExpr("RISE_TIME" sprintf(nil "MyRiseTime(v(\"/MIXER_I_P\" ?result 'tran) %g %g)" CLIP_START CLIP_END))

    What that does is load your custom function, but make it look like an expression that returns a number - and then uses it in the second monteExpr.

    Hope that helps,

    Regards,

    Andrew.

Children
No Data

Community Guidelines

The Cadence Design Communities support Cadence users and technologists interacting to exchange ideas, news, technical information, and best practices to solve problems and get the most from Cadence technology. The community is open to everyone, and to provide the most value, we require participants to follow our Community Guidelines that facilitate a quality exchange of ideas and information. By accessing, contributing, using or downloading any materials from the site, you agree to be bound by the full Community Guidelines.