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PAC Simulation: outputperiod option

ahchang

I want to do a time integration of my PAC simulation over one period. I did the simulation and I obtained a pac.real.pac file.  For some reason, I could not read the result from this file the same way as other files.  The normal Cadence command does not allow me to read data from pac.real.pac and I also cannot see the result directly from ADE (Results Browser or Direct plot).  Does anyone know how to open the simulation result from such file?



Thank you,

Albert


As an example, I can only see the following outputs even though the file pac.real.pac exists in the psf folder.

   'pss-td.pss'
   'pss-fd.pss'
   'pac-pac'
   'modelParameter-info'
   'element-info'
   'outputParameter-info'
   'designParamVals-info'
   'primitives-info.primitives'
   'subckts-info.subckts'
   'variables'
Parents

  • Recently, I've found that there is an option called "outputperiod" in PAC simulation.  According to the reference manaul, it lets you see the time-domain small-signal response. I am curoius on how this time domain small signal reponse is computed in Cadence. 

    This is how I've simulated with the output period option with period equal to 1ns.

    pac  pac  sweeptype=relative  relharmnum=0  start=0
    +    annotate=status  freqaxis=out  outputperiod=1n

    I've tried to  simulate the circuit without the outputperiod option and computed the time response myself.  The settling below gives me 50 harmonic output sidebands.  I then take the reverse fourier transform to obtain the time function.The input frequency is at a single point: 0Hz.

     pac  pac  sweeptype=relative  relharmnum=0  start=0
    +    maxsideband=50  annotate=status  freqaxis=out 

    I compute the time domain output by the following equation for each time point t: 

    H(0; t) = sum_{m = -50}^{m = 50} H_{m}(0) * exp(j * m * wc * t)

    where H_{m}(0) represents the mth harmonic relative to the input (0Hz) at DC. wc is the fundamental frequency = 2*pi/(1ns).

    For some reason, I did not get the same time domain waveform as if I directly use the Cadence outputperiod option. I've checked my math a few times, but I didn't see any problems.  The outpuperiod gives more correct result.   Could anyone please clarify how Cadence compute this output?

     

     Many thanks,

     

     

    Albert

     

Reply

  • Recently, I've found that there is an option called "outputperiod" in PAC simulation.  According to the reference manaul, it lets you see the time-domain small-signal response. I am curoius on how this time domain small signal reponse is computed in Cadence. 

    This is how I've simulated with the output period option with period equal to 1ns.

    pac  pac  sweeptype=relative  relharmnum=0  start=0
    +    annotate=status  freqaxis=out  outputperiod=1n

    I've tried to  simulate the circuit without the outputperiod option and computed the time response myself.  The settling below gives me 50 harmonic output sidebands.  I then take the reverse fourier transform to obtain the time function.The input frequency is at a single point: 0Hz.

     pac  pac  sweeptype=relative  relharmnum=0  start=0
    +    maxsideband=50  annotate=status  freqaxis=out 

    I compute the time domain output by the following equation for each time point t: 

    H(0; t) = sum_{m = -50}^{m = 50} H_{m}(0) * exp(j * m * wc * t)

    where H_{m}(0) represents the mth harmonic relative to the input (0Hz) at DC. wc is the fundamental frequency = 2*pi/(1ns).

    For some reason, I did not get the same time domain waveform as if I directly use the Cadence outputperiod option. I've checked my math a few times, but I didn't see any problems.  The outpuperiod gives more correct result.   Could anyone please clarify how Cadence compute this output?

     

     Many thanks,

     

     

    Albert

     

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