Re: Anybody with an oscilloscope as an Apple II display?

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

Michael J. Mahon wrote:
> On Mar 25, 9:51 am, heuser.mar...@freenet.de wrote:
>
> > Something on the line of this here:http://www.youtube.com/watch?v=s1eNjUgaB-g
> >
> > Maybe not as detailed but is it feasible at all?
>
>
> You need dual D/A's to generate such a display.  The speed with which
> the outputs
> can be changed--which soon becomes the speed with which the outputs
> can be
> computed, is what limits the complexity of the display.
>
> Although it is possible (with appropriate analog post-processing) to
> generate
> a straight line segment by sending just the new end point (a vector
> display),
> in practice one would send several intermediate points so that simple
> low-
> pass filtering would produce the desired trajectory.
>
> It's actually an older form of computer graphical output, since it
> preceded
> raster graphics by a decade or more.

I implied but didn't say that the outputs of the two D/A's
drive the X and Y axes of the oscilloscope, and in the video
the intensity is left unmodulated except by the velocity of
the beam.

Using a single-bit D/A to control the intensity would actually
simplify the problem somewhat for the Apple.

-michael

NadaPong: Network game demo for Apple II computers!
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