[sdiy] Waveshaping LFO Circuits

[mirwin at qouest.net]

Hello List,
Here are a couple of experimental variable waveshape oscillator designs 
using the LM13600. The waveshaping is done in the oscillator core rather 
than by processing a previously generated waveform.

The waveshape is smoothly variable from upramp through triangle to 
downramp under voltage control. Voltage controlled rate is provided in 
the 2nd schematic. There is a small variation in rate as the waveshape 
is changed (making it unsuitable for use at audio freqs) but some may 
want to try it for LFO applications or use it as a starting point for 
better designs.

The EMS VCS3 oscillators provide variable waveshaping using a different 
approach.

The schematics are here (Sam Hoshuyama's website):

http://www5b.biglobe.ne.jp/~houshu/synth/mike_irwin/V-LFO.gif
http://www5b.biglobe.ne.jp/~houshu/synth/mike_irwin/V-LFO2.gif

Regards, Mike