Re: Votrax chip SC01/SC02

["Michael J. Mahon" <mjmahon@aol.com>]

Allen Bong wrote:
> On Aug 29, 1:11 pm, "Michael J. Mahon" <mjma...@aol.com> wrote:
>
> > Allen Bong wrote:
> >
> > > On Aug 29, 3:28 am, "Michael J. Mahon" <mjma...@aol.com> wrote:
> >
> > > > zwsdot...@gmail.com wrote:
> >
> > > > > On Aug 27, 7:13 pm, "Michael J. Mahon" <mjma...@aol.com> wrote:
> >
> > > > > > The SC-02, more commonly known as the SSI-263, is a phoneme- or
> >
> > > > > Where is the Votrax SC-02 more commonly known as the SSI-263? :)
> >
> > > > Votrax apparently had SSI manufacture the chip for them, and SSI
> > > > took it to market as the SSI-263.  I've never seen a chip labelled
> > > > SC-02 (though they may be inside Votrax products), but I've seen
> > > > lots of SSI-263 chips.  There are still folks selling old stock
> > > > SSI-263's.
> >
> > > > I have seen several SC-01's, but they don't seem to be available
> > > > any more.
> >
> > > > > This is why the General Instruments SPO256A-AL2 allophonic speech
> > > > > processor was a better pick; it had the companion CTS256A-AL2
> > > > > processor IC that turned an English ASCII stream into an allophone
> > > > > stream.
> >
> > > > Making a minimum 2-chip solution--a bad match for a microcomputer
> > > > that already has a processor and memory available.
> >
> > > > Hmmm, no one's mentioned the TI LPC chip yet...   ;-)
> >
> > > > -michael
> >
> > > > NadaPong: Network game demo for Apple II computers!
> > > > Home page:  http://members.aol.com/MJMahon/
> >
> > > > "The wastebasket is our most important design
> > > > tool--and it's seriously underused."
> >
> > > In the game "Dung Beetles"  by Bob Bishops (???), he was able to
> > > pronounce the phase "We've got you!" without any extra hardware.  How
> > > did he do it?
> >
> > Check out my web page (referenced below) for a history of sound on
> > 8-bit Apple II's and several programs that use the Apple speaker
> > with a 5-bit software DAC to produce sounds of pretty good fidelity.
> >
> > Most games used the speaker in a 1-bit mode with a sample rate around
> > 8-12KHz to play back "infinitely clipped" sound.  As you probably
> > remember, it sounds very gravelly, and uniformly loud.
> >
> > SAM also uses the speaker in a "software DAC" mode to reproduce
> > phonemes with reasonable fidelity.
> >
> > -michael
> >
> > NadaPong: Network game demo for Apple II computers!
> > Home page:  http://members.aol.com/MJMahon/
> >
> > "The wastebasket is our most important design
> > tool--and it's seriously underused."- Hide quoted text -
> >
> > - Show quoted text -
>
>
> Hi Michael,
>
> Thanks for your great web site.  I will take a closer look on the
> sound generation portion.

Thanks!

> As for SAM I dont think it is a totally software-dependent speech
> generator.  I just dug out my card and I found that there is a
> AM1408N6, a 74LS273 and a 386 audio amp on it.  Isn't 1408 an 8-bit
> DAC chip?

Right.

There were two versions.  One used software to generate the samples
and then sent them to a real DAC on a plug-in card (as you describe),
and the other generated a multi-bit PWM signal through the standard
Apple II speaker.  The tricky part is that it did the synthesis at
the same time it was generating the PWM signal!  (Like the way that
RT.SYNTH and CRATE.SYNTH generate instrument voices on the fly as
they are generating PWM pulses.)

-michael

NadaPong: Network game demo for Apple II computers!
Home page:  http://members.aol.com/MJMahon/

"The wastebasket is our most important design
tool--and it's seriously underused."