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How to choose a monitor
The most important specifications
Will you show computer images with your new monitor? If so,
what resolution will it need to display? Resolution measures
the amount of detail that can be seen in a video or computer
image, expressed as the number of lines visible on a test
pattern. VGA requires 640 x 480 resolution, S-VGA 800 x 600,
XGA 1024 x 768, SXGA 1280 x 1024, UXGA 1600 x 1200 and engineering
workstations can run higher. Another way to express these
resolutions is in scan rates, and, for those with specialized
graphics cards or workstations, we have included those in
our comparison charts as well.
video source. Do you need to show S-video or just composite?
Will you need to show tapes from overseas in PAL or SECAM
format? Will you need to show the new digital HDTV format?
If you do need HDTV, a component input is the preferred connector.
Though the new digital systems also have composite inputs,
the component connector will reduce noise by minimizing crosstalk
within the video signal.
resolution is a key specification that can serve as an
overall indication of the picture quality of the monitor.
Normally your monitor's resolution will be higher than your
source: VHS is about 220-260 lines, VHS-HQ 300, off-air TV
signals just over 300, S-VHS 400-440. Strictly speaking, a
monitor offering higher resolutions is a waste if you're showing
standard video, but most viewers will agree that it looks
better, because of a number of factors that don't show up
in the specs.
When looking at new digital video formats, resolutions
get much higher. There are four DTV bandwidths that will be
commonly used. To show 480i images at full resolution, your
monitor must be able to show 640 x 480 lines; 480p requires
704 x 480, 720p requires 1280 x720, and 1080i requires 1920
x 1080. In practice, most monitors won't display 1080i or
even 720p resolutions, and so they will simply show these
signals at the highest resolutions they are capable of.
interlaced scanning are becoming important considerations
with DTV formats. Interlaced scanning, used in all analog video
monitors, interlaces two pairs of fields, each containing half
the scan lines. Progressive scanning, used in most computer
monitors and new 480p and 720p DTV formats, scans the entire
picture as a single frame. Image quality is significantly better
with progressively-scanned pictures.
also becoming important with digital formats. Standard video
has an aspect ratio of 4:3—that is, the ratio 4 to 3. HDTV (1080i
and 720p), however, uses a wide screen ratio of 16:9, which
is the aspect ratio used for movies. A monitor built to either
aspect ratio will show both, but if you want to fill the screen
with the best possible image, you need a unit with the ratio
that matches what you most often view.
size vs. audience size. Rules about monitor sizing seem
to be ignored more often than followed, but you need to be
aware that, if you stretch these rules, viewability becomes
a real issue.
Current thinking is that the maximum viewing distance for
video sources should be about eight times the height of the
image and for computer about six times. This formula works
for both traditional 4:3 aspect ratio monitors and 16:9 wide-screen
sets, but if you show a wide screen image on a standard monitor,
the top and bottom of the screen will not be used. Thus the
image height and viewing distance will be about 25% less.
(Showing 4:3 images on a 16:9 monitor does not affect viewing
The person farthest away in your audience should be no more
4:3 aspect monitors
Full screen 4:3 video
Full screen 4:3 computer
Masked to 16:9 video
Masked to 16:9 computer
Masked to 4:3 video
Masked to 4:3 computer
Full screen 16:9 video
Full screen 16:9 computer
video inputs: The difference between a monitor (or monitor/receiver)
and a television is important: the monitor has direct video
and audio inputs, the pure receiver only an antenna input.
Having a video input means that a videotape or disc image
will be much clearer. Using a television, you have to convert
the video signal to radio frequency, then convert it back
again to video (that's what you're doing when you use the
RF output on the VCR and channel 3 or 4 on the receiver).
The two extra steps add quite a bit of noise.
same way, S-video inputs are not necessary to show
an S-video tape, as all S-VHS and Hi-8 VCRs have S, composite
and RF outputs. But a monitor with S inputs will show S-video
images at a higher resolution and with much less noise cased
by crosstalk between the chroma (color) and luma (detail)
signals, because it carries these signals on separate cables.
video inputs separate
the signal into three parts, dividing the chroma into red,
green and blue components (with luma included with the green).
A component signal is as clean as S-video, but offers much
more color detail. You'll find component connectors on DTV-ready
monitors and projectors, DVD players and digital VCRs.
kind and number of computer inputs are also important.
Most PCs and Macs require analog RGB inputs; some older and
some specialized systems will require TTL inputs.
an important specification, though not generally provided
by CRT monitor manufacturers. It is, however available for
many plasma units, given in cd/m2, or candellas per square
UL approval means that the unit has be rated as safe for
use is a school or business. These safety standards are higher
than those for a home.
Beyond the basics, you'll want to consider whether or not your
new monitor includes:
inputs and outputs allow you to switch between more than
one computer or video source
means that the unit has video (or computer) and audio outputs
as well as inputs allowing you to daisy-chain monitors or
use your desktop computer monitor at the same time as your
scanning allows the monitor to sense the incoming computer
or video signal and lock onto it without adjustment. All of
the monitors United Visual offers have this feature, but many
older or lower quality units do not.
mode memory, available in many computer monitors, stores
any adjustments you make for a given input separately from
those for a different input.
tuner allows you to access broadcast or cable programming.
A tuner is not a necessity if you're using a VCR (as most
VCRs already have tuners).
VCR can also be useful, particularly if you have limited
space or are planning to transport the unit.
menus simplify the accurate setup or adjustment of many
programming allows you to set up one unit the way you
want it, then copy all settings to additional monitors. It
can make a big difference in business networks and video distribution
settings, as an initial time saver and a tool to keep image
quality high on every monitor.
features, whether event programming or a simple on/off
timer, can be very useful for monitors used in public displays
features, such as channel lock, a removable mask or more
advanced control lock features, are important for pubic displays
and classroom networks, where viewers might change settings.
features, such as overscan/underscan, rack mounting, and
sync input, are available in monitors from United Visual,
though we have not included them in this on-line catalog.
Please call for details.
Beyond the specifications
Comparing specifications will take you only so far in choosing
a computer or video monitor. You'll need to see the unit demonstrated
or talk to your dealer to get a feel for:
How long will a monitor last? Does its manufacturer have a
good reputation? What's the warranty?
How quickly can your monitor be serviced if it fails? Are
you purchasing it from an authorized service center? If not,
what will you do when it needs repair?
and squareness of the picture tube is a consideration
for the overall image quality and the impression you'll make
on your audience. It is also an indication of the age of the
technology going into the monitor's manufacture.
quality. We have not listed detailed audio specs for the
monitors in this catalog, as they are typically not available
from monitor manufacturers. But audio can be important, and
an audience will perceive an identical image to be of higher
quality if the accompanying sound is better