Re: Glass Cockpits' Video Rates?

From:         rogerc@dev1.ssd.fsi.com
Organization: FlightSafety Simulation Systems Division - Tulsa
Date:         01 Nov 94 00:06:53 
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> In article <airliners.1994.1644@ohare.Chicago.COM>,
> philip_decker@lds.loral.com writes:
> > Am curious about the characteristics of the video signals displayed in
> > glass cockpit aircraft: sync frequencies, resolution, (non)interlace,
> > etc...  Also, are all the displays (vertically) sync'd to each other?
> > 
> As far as I know all glass cockpit displays are caligraphic, not raster.
> Caligraphic displays offer much higher contrast and brightness.  Refresh 
> frequencies can be increased to increase brightness.
> 
> (Caligraphic displays draw the lines and curves Etch-A-Sketch style.)
> 
> Disclaimer:  I have not had a peek in any of the more modern glass 
> cockpits.  This is from 757 and 767 observations.
> 
> 					Michael Drews

I'm not familiar with the details of how the new flat panel displays
are driven as in the new Boeing 777 aircraft, but the typical EFIS
display used throughout the industry receives raster video and stroke
(vector) video.  It is true the stroke video handles a major portion
of the graphics such as text, lines, and symbols.  Raster display
however is still required or at least is used to quickly fill large
areas of the display such as the sky/ground background and weather
radar video. EFIS tubes which provide for both raster and stroke
display apparently don't come cheap either.  For simulation purposes,
the EFIS displays will usually be pure raster graphics (much cheaper)
and the resolution is quite nice.  Hope this explains a little more.

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|  Roger Chandler                     |                                                
|  Senior Engineer - Navigation/Visual|
|  FlightSafety International -       |
|  Simulation Systems Division        |
|  Ph: 918-251-0500  Fax:918-251-5597 |
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