[sdiy] random thought about sine shapers

[David G. Dixon]

> This is where using an overdriven OTA as a sine shaper is good:
> if you keep cranking up the input, you get a progressively more
> squared off output.
> So you can, by increasing input level, go from triangle thru sine to
> square,
> The output level increases a bit as you do this, but not all that much.

Yes.  A plain ol' differential NPN pair feeding a differential opamp does
exactly the same thing, with slightly better THD specs (I think), as long as
the correct component values are used.

> Of course, overdriving an 'ordinary' sine shaper would give a waveform
> change as well.

I'm not sure what you mean by 'ordinary'.  I figure all sine shapers do the
same thing; namely, take advantage of the tanh distortion of differential
pairs.  I'm not sure how "square-y" mine will go, as I don't think I've ever
cranked the pot that far.  I know it will reproduce the input waveform,
though.