Saga of the uP developer

[Curtin, Steven D (Steven)]

This is indeed an old and venerable idea.  A digital version of this, with
ramp counters controlling the slew rates, was the core of the Buchla digital
MARF used in the 400 and Touche.  The SalMar Construction used
digitally-controlled analog slew rate limiters, with analog switches turning
on and off combinations of resistors.   Of course it's still a good idea,
and it's great to see ideas like this resurfacing in new designs.

Steve C

-----------------------------------------------------------------
Steven Curtin  
Lucent Technologies Microelectronics
ph: (732)949-4404   fax: (732)949-6711
http://curtin.emf.org
sdcurtin at lucent.com
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> ----------
> From: 	Jim Patchell[SMTP:patchell at silcom.com]
> Sent: 	Tuesday, June 27, 2000 10:07 AM
> To: 	Paul Maddox
> Cc: 	Fraser, Colin J; Synth-DIY
> Subject: 	Re: Saga of the uP developer
> 
>     Darn....There are no original idea's.  I have something like this on
> my
> drawing board.  Thought I was being cleaver.
> 
> Paul Maddox wrote:
> 
> > Colin,
> >
> > >
> > > The CPU sends two voltages to an expo slew circuit, with a comparator
> > input
> > > back to the CPU to tell it when the peak value is reached (end of the
> > attack
> > > phase).
> >
> > nice trick..
> > but how do you get the rate to change?
> >
> 
>     You need two voltages.  One controls the time constant, the other
> controls
> the voltage that you ramp to.  The one advantage I saw to doing EG's this
> way
> was that you can have as many segments as you want to the contour.  Also,
> you
> can have the time constant circuit do either linear or exponential ramps
> without too much trouble.
> 
>