matt@prism.UUCP (09/18/85)
Reproduced without permission from INFOWORLD (Sept. 18, 9815):
A new graphics board from a division of AT&T lets standard IBM color
displays produce images with as many as 256 colors simultaneously, 32
times the existing limit.
The $695 VDAD (visual display adapter/digital) graphics board ...overcomes
the inherent limit in the current digital RGB monitor, which normally can
display only eight colors in two intensities at a time.
Engineers at the [AT&T Electronic Photography and Imaging] center added
the Bell Labs techinique [for pulse width modulation] to their existing
VDA board, thus creating a digital version with the same 32,768 color
palatte and the capability to display a selection of 256 colors from that
palatte on the [standard IBM PC color monitor] screen, with a resolution
of 256 by 200 pixels.
Although the VDAD board has low resolution, the capability to select any
combination of 256 colors from a large palatte gives the resulting picture
a realistic quality.
Hmmm... 256 out of 32K colors on a standard PC color display? Sounds
interesting. I wonder if they're working on a higher resolution version
that would run on the EGS (256 by 350 pixels, perhaps?)
-----------------------------------------------------------------------------
Matt Landau {cca, ihnp4, inmet, mit-eddie, wjh12}...
Mirror Systems, Inc. ...mirror!prism!matt
Cambridge, MA (617) 661-0777
-----------------------------------------------------------------------------sdyer@bbncc5.UUCP (Steve Dyer) (09/23/85)
> Hmmm... 256 out of 32K colors on a standard PC color display? Sounds > interesting. I wonder if they're working on a higher resolution version > that would run on the EGS (256 by 350 pixels, perhaps?) No, on a color composite video monitor or analog RGB display. It's impossible to display more than 16 colors on an IBM-CGA-compatible monitor or 64 colors on an Enhanced Color Display: the RGB signals are digital, not analog, and there are only 4 separate inputs (or 6, for the ECD). -- /Steve Dyer {harvard,seismo}!bbnccv!bbncc5!sdyer sdyer@bbncc5.ARPA
sdyer@bbncc5.UUCP (Steve Dyer) (09/24/85)
> No, on a color composite video monitor or analog RGB display. It's > impossible to display more than 16 colors on an IBM-CGA-compatible > monitor or 64 colors on an Enhanced Color Display: the RGB signals > are digital, not analog, and there are only 4 separate inputs > (or 6, for the ECD). Um, I seem to have rushed in a bit quickly. The AT&T board works with composite video color monitors, but it also works (according to InfoWorld's report and ima!johnl's private communication) on digital IRGB displays by "flickering" the colors on and off to simulate levels of brightness. Good stuff, if it works (and doesn't fry your monitor!) -- /Steve Dyer {harvard,seismo}!bbnccv!bbncc5!sdyer sdyer@bbncc5.ARPA
peter@graffiti.UUCP (Peter da Silva) (09/25/85)
> No, on a color composite video monitor or analog RGB display. It's > impossible to display more than 16 colors on an IBM-CGA-compatible > monitor or 64 colors on an Enhanced Color Display: the RGB signals > are digital, not analog, and there are only 4 separate inputs > (or 6, for the ECD). Infoworld, Sep 16 1985: A new graphics board from a division of AT&T lets standard IBM-PC color displays produce images with as many as 256 colors simultaneously, 32 times the existing limit... [it] overcomes the inherent limit in the current digital RGB monitor... "We're using a technique patented by Bell Labs several years ago to increase the number of colors. It's a form of pulse-width modulation that tricks the monitor into thinking it has more than 1 level for each component." The board is called the VDAD, for Visual Display Adapter/Digital.
john@anasazi.UUCP (John Moore) (09/25/85)
In article <372@bbncc5.UUCP> sdyer@bbncc5.UUCP (Steve Dyer) writes: >No, on a color composite video monitor or analog RGB display. It's >impossible to display more than 16 colors on an IBM-CGA-compatible I believe that the AT&T board uses pulse width modulation to get a pseudo-analog effect on the RGB. Thus it is not really impossible. -- John Moore (NJ7E) {decvax|ihnp4|hao}!noao!terak!anasazi!john {hao!noao|decvax|ihnp4|seismo}!terak!anasazi!john (602) 952-8205 (day or evening)
larry@extel.UUCP (09/27/85)
The trick they use as I read in Electronics News is to play with the width of the RGB signals to fake the monitor into displaying more than the normal 16 colors. According to the article AT&T has a patent on this. Larry ihnp4!extel!larry
aaron@inuxg.UUCP (Jeffrey Walters) (09/28/85)
> > Hmmm... 256 out of 32K colors on a standard PC color display? Sounds > > interesting. I wonder if they're working on a higher resolution version > > that would run on the EGS (256 by 350 pixels, perhaps?) > > No, on a color composite video monitor or analog RGB display. It's > impossible to display more than 16 colors on an IBM-CGA-compatible > monitor or 64 colors on an Enhanced Color Display: the RGB signals > are digital, not analog, and there are only 4 separate inputs > (or 6, for the ECD). > -- > /Steve Dyer > {harvard,seismo}!bbnccv!bbncc5!sdyer > sdyer@bbncc5.ARPA WRONG Steve: The new graphics card from AT&T's Electronic Photography and Imaging Center (EPICenter) does display 256 colors (from 32K - color map) on the standard digital RGB PC color display. If anyone would like more information on the products offered by EPICenter please mail your name, address (US Mail) and phone number to ...ihnp4!inuxa!inuxg!epic. Jeffrey A. Walters Operations Manager EPICenter Please do not send mail to me for information requests but send to the above address (...ihnp4!inuxa!inuxg!epic).