Well, I guess at this point I'm kind of confused then. I would help if we could all see the results on a scope. That is, inject a test tone into the audio line, and show what happens to the modulation envelope when you exceed 100%.
I thought the basic idea behind NPC was that it _does_ give you asymmetrical modulation, though at the modulation stage rather than in the audio stage.
Your description (which I confess to not reading clearly at first) says that your mod just prevents the carrier from being pinched off. But you also say you don't do anything else to the waveform. Here's a really crappy drawing that shows two waveforms:
The line through the middle of each is 0 volts. Both are intended to have the same positive peak amplitude (the positive peaks extend 3 lines from the 0 volt line).
The first shows the typical over-modulated carrier, with the negative peaks bottoming out at 0 volts.
The second is intended to show the same thing, except here we don't let the output bottom out: the negative peaks are prevented from touching the 0 volt line.
Is that what your circuit is meant to do? If so, then I would expect there would still be some distortion: the negative peaks still flatten out even though they don't touch.
Again, I apologize if I'm just being dense here.
-Bill
