Simulation: NPR Test Simulation

So during my time at work today (yes I worked on Saturday), I made an attempt to try and simulate an NPR test for an amplifier in Agilent's EESof/ADS.  Now there is a way to accomplish this using the DSP portion along with the Analog Envelope technique but I haven't found a way to do it directly with the RF/Analog system.  This is quite the disappointment...

Figure 1: NPR Test Stimulus (courtesy Agilent)

So I have been researching into solutions.  Only one has presented itself up to this point: Spectral Balance Simulations.  Unfortunately, ADS doesn't support this directly (at least not to my knowledge).  This is different than the typical Harmonic Balance Simulation most people are used to.  In fact the main difference is that the Spectral Balance simulation stays in frequency domain.  The Harmonic Balance simulation instead does a transient analysis then an FFT to complete the simulation (Of course it's more complex than this).


So how do I get around it?  I really have no idea right now.  The fact is, this is a known issue.  Why hasn't someone developed this into the more popular SPICE simulations?  There are random Matlab tools that can do the trick but not directly in SPICE packages.


Anyways, that's my rant for the day.  I'll go into more detail, hopefully, at a later date.


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Justin Coulston
justin.coulston@gmail.com