Re: CineSound Samples

From: Joseph J. Welser <jwelser_at_crystal.cirrus.com>
Date: Wed Jul 23 1997 - 11:20:37 EDT

> No, I'm not confused :-) That's exactly what I meant. Simulate the RC circuit
> and the VCO. Using pitch bend might introduce noise where simulating
> the VCO is easy since the output needs to be a relatively low frequency
> square wave.

        OK, but just so you know, it's not a simple RC circuit, there is a clamping diode in there too. I think it's called the "Level Shifter and Limiter" block by Cinematronics.

        You can get a copy of the 566 VCO datasheet from National Semiconductor's web site (www.national.com) I think I have mine here......Yeah, here it is -- the formula for fout is:

        fout = 2.4(V+ - V5)
               _____________
                 Ro Co V+

        where 2k < Ro < 20k

        and V5 is the voltage between pin 5 (labeled modulation input) and pin 1 (GND)

        I have my notes around here somewhere, where I already plugged the numbers into that formula, so I'll post that later.....Just make sure you look at the schematics....

> And yes, I'd like to add sound to the emulator :-) I find the Zonn idea of
> using MIDI very interesting, but I'll just be using the Windoze stuff. At
> this point I'm only interested in sampling the triggered sounds, but I will
> try to emulate the VCO stuff once the rest is working.

        That should be easy. You can emulate a S2688 EXACTLY, if you want. We talked about this one too a couple of months ago. (BTW, Zonn, I eventually DID find a full-blown datasheet for the S2688 -- About 2 weeks ago, a lab tech here was recycling old databooks, and I hit paydirt. Among the stuff there was a Gould Electronics (who bought AMI) databook)

        Oh wait a sec, I forgot that you're sampling the sounds....never mind.....

Joe

------------------------------------------------------------------
Joseph J. Welser jwelser@ccwf.cc.utexas.edu
Design Engineer jwelser@crystal.cirrus.com
Crystal Semiconductor Corporation http://www.crystal.com
P.O. Box 17847
Austin, TX 78760
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Received on Wed Jul 23 08:18:17 1997

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