[sdiy] Variable waveform LFO

[harrybissell at copper.net]

There was talk of such a thing and
Don Tillman has his ides (schematic)
on his site. It was a waveshaper, not
a complete VCO (iirc)

H^) harry



>
>
>
>---- Original Message ----
>From: profpep at hotmail.com
>To: ijfritz at comcast.net, synth-diy at dropmix.xs4all.nl
>Subject: RE: [sdiy] Variable waveform LFO
>Date: Fri, 12 Jan 2007 18:07:19 -0000
>
>>>.  This helped when I was working on SNIC circuits.
>>>
>>> http://home.earthlink.net/~ijfritz/sy_cir10.htm
>>>
>>Looking at this, I vaguely remember a circuit for a variable
>waveform
>>oscillator from years ago, working on a function generator
>principle. It
>>depended upon a switchable current mirror, (I think), in the
>charging
>>circuit. This allowed the main waveforms to be varied from a
>positive decay
>>sawtooth via a triangle  to a negative decay sawtooth, on one
>output, and
>>from about a 5% to a 95% mark-space squarewave on the other. I'm
>sure it's
>>around somewhere, but I've not seen it recently. I'm not sure if it
>was
>>stable enought for a main VCO, but it made an interesting and useful
>LFO.
>>
>>Any suggestions, or is my google-fu not good enough?
>>
>>||\/||ike