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New Fast Envelope in MMSIM10.1 is *Really* Fast and Accurate!

Comments(0)Filed under: MMSIM, RF, envelope, simulation, fast envelope

Traditionally, envelope analysis is used to simulate circuits with modulated inputs. 

Envelope analysis is much faster than transient simulation, and is used for simulating spectral regrowth.  


Regular envelope analysis is "brute force" transistor-level simulation:

  • Simulation time for traditional envelope analysis can take hours to days, depending on designers’ specified stop time for simulation.
  • It's accurate and includes all the nonlinearity effects.

Fast envelope analysis technology uses an accelerated mathematical representation to reduce the computational complexity

  • The circuit is automatically calibrated and replaced by an accelerated mathematical representation without the designer's intervention.
  • Simulation completes in minutes, independent of the designer’s specified stop time.
  • Good compromise between computational efficiency and accuracy.

Simulations that used to take days now take hours or minutes with no loss in accuracy!

There is an easy to use GUI and use-model in MMSIM 10.1:

 There are 3 modes available for fast envlp analysis:

  • off:  regular envlp analysis (default)
  • level1: fast envlp analysis in level 1(for circuits with short memory)
  • level2: fast envlp analysis in level 2 (more accurate)

Run fast envlp with a fixed step size.  Set the step period to the I/Q data sampling rate.

Select the I and Q modulation sources on the schematic, as well as the output node(s) of the PA.

In summary:

  • Fast envlp is easy to use.
  • Orders of magnitude faster than regular envlp analysis.
  • Accuracy is very good.
  • Fast envlp is used for simulating spectral re-growth (ACPR, ACLR).
  • Fast envlp is supported in the ADE GUI in IC and IC .

Have fun simulating!

Tawna Wilsey


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