[sdiy] What is a quadrature oscillator good for?

[Mike Brown]

Hi Grant,
I know that Thomas Henry has a quadrature LFO in his book, "Build a Better
Synthesizer"...

I always had this idea that I was going to build his circuit, invert the
outputs, and do the quad panning thing.  another idea was to use a
quadrature LFO to pulse width modulate or frequency modulate four separate
VCOs.... or sweep four VCFs, etc. etc.

a useful device, IMO.

regards,
Mike Brown

----- Original Message -----
From: "Grant Richter" <grichter at asapnet.net>
To: <synth-diy at dropmix.xs4all.nl>
Sent: Monday, September 08, 2003 7:51 AM
Subject: [sdiy] What is a quadrature oscillator good for?


> I have been doing a lot of digging in the local public library for
odd-ball
> waveshaper ideas.
>
> I found an interesting simple waveshaper to generate a quadrature signal
> from a triangle oscillator core. It's from an old Electronics magazine
> article (70s). I will put it up when I get a chance.
>
> Aside from frequency shifters and qudraphonic panning, is there anything
> else a quadrature oscillator is good for?
>
> I am prototyping a linear through-zero quadrature LFO to use with the
> Joystick Axis Generator (reverses panning direction with negative
voltage),
> I am curious if there are any other non-proprietary applications people
> would share?
>
> Also, are there other quadrature LFO designs out there? So I can properly
> credit references.
>
> Thank you for any help.