DVI comes in several flavors--digital only and analog plus digital; there
are enough pins to provide both. But if your DVI output is digital only--as
is usually the case at this stage of developemtn-- an adaptor cannot provide
analog from that connector. The standard analog 15-pin plug is likely to be
around for quite a while, as there are literally zillions of legacy analog
monitors out there!
Attenuation and phase distortion in long video cables carrying high-speed
analog video (SXGA and higher, especially with high refresh rates)causes
loss of image quality. The video cable is, after all, a set of transmission
lines. This was not a problem with 640x480 VGA monitors with 60 Hz refresh
rates and short (6') cables, but has become an issue with SXGA (1280x1024)
and higher speed displays, especially with higher refresh rates (85 or 100
Hz and more). The characteristic impedance of these cables seems not to be
well controlled, either.
These effects are greatly reduced by the use of digital video, especially
when long video cables are used, as in connecting a computer to a
wall-mounted display.
Another contributor to loss of image quality is the fact that your computer
generates digital video, which is converted to analog on your video card and
sent on to your analog monitor. To use that same analog video to drive a
solid-state panel display requires analog to digital conversion at the
display--that's two conversions and an analog transmission means. Utilizing
digital video to directly drive a digital display can lower cost and
preserves image quality. Moreover, an analog monitor can also benefit from
DVI---a higher quality display is obtained by performing the D to A
conversion right at the neck of the CRT, instead of back at the video card!
Garry, NI6T
-----Original Message-----
From: writelog-bounces@contesting.com
[mailto:writelog-bounces@contesting.com]On Behalf Of Jim McDonald
Sent: Saturday, November 29, 2003 1:45 PM
To: writelog@contesting.com
Subject: Re: [WriteLog] 2 monitor question
Ed,
The connector is different to begin with. I saw one note on the reflector
that an adapter plug is available, but I don't know how reconfiguring
connections could work. So my opinion is that it can't be done.directly.
I don't know what percentage of the current offerings of flat panel monitors
have the DVI input or, better yet, both DVI and analog, but it's an
advantage, it seems to me. (Now, if I only understood flat panel TVs,
digital, HD, etc.!)
Jim
----- Original Message -----
From: "K4SB" <k4sb@earthlink.net>
To: <writelog@contesting.com>
Sent: Saturday, November 29, 2003 1:30 PM
Subject: Re: [WriteLog] 2 monitor question
Jim McDonald wrote:
My Dell 8300 came with an NVIDIA GeForce FX 5200 video adaptor
> with 128M RAM. It has a DVI (digital) output and an analog (15-pin) one.
I
> have the PC's DVI port connected to the new monitor's DVI port.
----------------
What would be the effect if the DVI port were connected to a regular
monitor? Or is that possible?
73
Ed
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