Simulators and clipping

[rtarbell]

I've run the same circuit in both full versions of AIMspice and TopSpice with this hicup in transient analysis (AC analysis runs fine). My circuit is rather large and complex.

My input source is a sine wave generator. When I raise the amplitude at the input large enough to make the amplifier clip, the output waveform gets all "fuzzy", it has lots of spikes on it. When I lower the amplitude to just below clipping, the output waveform is fine, nice and smooth.

I'm just wondering, is there anything I can do to smooth this out, or is it somethign I have to live with?

[jackinnj]

Originally posted by rtarbell
I've run the same circuit in both full versions of AIMspice and TopSpice with this hicup in transient analysis (AC analysis runs fine). My circuit is rather large and complex.

My input source is a sine wave generator. When I raise the amplitude at the input large enough to make the amplifier clip, the output waveform gets all "fuzzy", it has lots of spikes on it. When I lower the amplitude to just below clipping, the output waveform is fine, nice and smooth.

I'm just wondering, is there anything I can do to smooth this out, or is it somethign I have to live with?

if you have an FFT on your sim program you can see all the harmonics mushroom out of nowhere --

[darkfenriz]

Originally posted by rtarbell

I'm just wondering, is there anything I can do to smooth this out, or is it somethign I have to live with?

I don't understand what you mean. It looks like your sim does its job well, deep saturation of several stages can produce some peaks and even loss of stability for a moment, because capacitances of active devices are getting much higher at saturation. If you don't like the effect you can trade saturation of active devices for switching of fast diodes.

[Frenchman]

Don't drive your amplifer into hard limiting. That's really your only solution. If you'd like to know WHY it's getting all fuzzy, that's a different question.