[sdiy] Analog Computers ( again )

[Aaron Lanterman]

On Feb 9, 2009, at 9:22 PM, David G. Dixon wrote:

>> From what I understand, the state-variable filter we use in synths  
>> is also
> an analog computer for the general mass-spring-damper second-order
> differential equation problem from Newtonian physics.  Voltages  
> representing
> displacement, velocity and acceleration are tapped off from various  
> points
> within the filter circuit.  It's all very easy to do with Laplace  
> transforms
> (apparently).

I do a lecture on this in my Electronics for Music Synthesis class):

http://blip.tv/file/777499 (about half an hour in)

Also see here:

http://web.mit.edu/2.161/www/Handouts/LPOpAmp.pdf

- Aaron