Re: pixelvision concept

["Alexander the Great jr." <kanaris@bode.usc.edu>]

> 

>     Alexander> PXLvision works because it uses a higher than normal

>     Alexander> tape speed, 8x or something like that, which roughly

>     Alexander> allows for 8x bandwidth, then trades off vertical

>     Alexander> resolution for horizontal resolution.  So, instead of

>     Alexander> 400 horizontal lines, you get only 100. That gives you

>     Alexander> four times more pixels per line.

> 

> 

> It also, from the footage I've seen, trades off greyscale depth for

> horizontal resolution.

> 

> Brent



It sure does, otherwise it wouldn't be possible to pack so many

pixels (something like 128*96) at 8 bits of resolution!!

It is probably only 5 or 6  :-) 



The encoding uses both the frequency and amplitude space, probably

something like Trellis coding, if you know what I'm talking about. 



You can pack about 8-10 bits in each audio cassette "sample".

(Based on the typical SNR figures). Don't think about the encoding

as purely "digital", i.e. only 1s and 0s. 





    <<alex kanaris>>  



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Alexander Kanaris                           ___   ___     kanaris@bode.usc.edu

Electrical Engineering --- Systems   /  /  /__   /      kanaris@thales.usc.edu

University of  Southern California  /__/  ___/  /__     kanaris@aludra.usc.edu

Los Angeles, California 90089-2562                  kanaris@alumni.caltech.edu

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