Square 2 Sine Shaping
1999-11-04 by Tkacs, Ken
Okay, I found it. It wasn't on the Analog Devices site; it was Harris, now Intersil. Go to Intersil.com and look under their application notes for "Derive Pure Sine Waves from Digital Signals (HA-2841)." The technique would need adapting, but it's something I hadn't seen before. I imagined replacing the resistors with 16 pots (VCAs?) for adjustable waveshaping; haven't played with it at all though. Filtering is a critical factor in this circuit.