PC Hardware in a Nutshell, 3rd Edition [Electronic resources] نسخه متنی

16.1 CRT Monitors

Like a television set, a monitor
comprises a cathode ray tube
(CRT) and supporting circuitry that processes
the external video signal into a form that can be displayed by the
CRT. Monitors use a different video interface than televisions, have
much higher bandwidth, and can display much finer detail. In fact,
with the proper adapter, computer video signals can be displayed on a
standard television, but only at low resolution. Conversely, a
monitor can be used to display television video at very high quality,
although doing so requires using a video card with TV input, a tuner,
and other electronics that are built into television sets but not
monitors. The quality of the CRT and supporting circuitry determines
the quality of the image a monitor can display. Because of their
higher bandwidth and resolution, computer monitors cost much more
than televisions with equal screen sizes.

Monitors comprise the following major
elements:

The CRT is essentially a
large glass bottle, flat or nearly so on one end (the screen),
tapering to a thin neck at the back, and with nearly all air
exhausted. The inside of the screen end is covered with a matrix of
millions of tiny phosphor dots (or stripes). A
phosphor is a chemical compound that, when struck by electrons, emits
visible light of a particular color. Phosphors are organized by
groups of three, collectively called a pixel.
Each pixel contains one phosphor dot that emits each of the additive
primary colors red, green, and blue. By choosing which dots to
illuminate and how brightly to illuminate each, any pixel can be made
to emit any one of thousands or millions of discrete colors. For
example, 24-bit color allocates a full 8-bit byte to each of the
three primary colors, allowing that pixel to be set to any of 256
levels of brightness. Three colors, each of which can be set to any
of 256 brightness values, provides a total color palette of
256³ colors, or about 16.7 million colors.
The distance between nearest neighbors of the same phosphor color on
adjacent rows is called the dot pitch or
stripe pitch. A smaller pitch results in a
sharper image and the ability to resolve finer
detail.

The phosphor dots are excited by one or more electron emitters,
called electron guns, located in the neck at the
back of the monitor. A gun comprises a heated cathode, which emits
electrons, and circuitry that focuses the free electrons into a thin
beam. Most CRTs use three separate guns, one for each primary color.
Sony Trinitron CRTs use only one gun. There has been much debate
about the relative display quality of single-gun versus triple-gun
CRTs, both of which have theoretical advantages and disadvantages. In
practice, we find the images indistinguishable. The quality of the
electronics used to control the shape and positioning of the electron
beam is very important to image quality because the relative position
of pixels to electron gun varies with the position of the pixel on
screen. Pixels near the center of the screen are oriented at 90
degrees to the gun, and are struck dead-on by the beam. Conversely,
pixels near the corners of the screen are struck by the beam at an
angle, which, in the absence of correcting circuitry, causes the beam
to assume an oval rather than circular shape. High-quality guns
correct this problem by changing the shape of the beam according to
the position of the pixel being illuminated. Lower-quality guns used
in inexpensive monitors do a much poorer job of adjusting the beam,
resulting in images blurring near the edges and corners of the tube.

The
deflection yoke is located around the tapered
portion of the CRT, between the guns and the screen. This yoke is
actually a large electromagnet, which, under the control of the
monitor circuitry, is used to steer the electron beam(s) to impinge
on the correct phosphor dot at the correct time and with the correct
intensity.

The
mask sits between the electron guns and the
phosphor layer, very close to the latter. This mask may be a sheet of
metal with a matrix of fine perforations that correspond to the
phosphor dot triads on the screen, or a series of fine vertical wires
that correspond to phosphors laid down in uninterrupted vertical
stripes. The perforations or stripes permit properly aimed electrons
to impinge directly on the phosphors at which they are aimed, while
blocking excess electrons. This blocking results in a cleaner image,
but blocked electrons heat the mask. To prevent differential heating
from distorting the mask, the mask is often constructed of Invar (an
alloy with an extremely low coefficient of thermal expansion) or a
similar material. Although the mask improves image sharpness, it also
dims the image because areas blocked by the mask cannot emit light,
so design efforts focus on minimizing the percentage of screen area
blocked by the mask.

In practice, and despite the marketing efforts of manufacturers to
convince us otherwise, we find that the mask type makes little real
difference. Good (read expensive) monitors produce good images,
regardless of their mask type. Inexpensive monitors produce inferior
images, regardless of their mask type. Monitors from the best
makersHitachi, NEC-Mitsubishi, and Sonyproduce superb
images using different masking methods. That said, however,
there's no substitute for looking at the monitor
yourself. You may have a strong preference for the type of picture
produced by one of the following mask
types:

The Sony Trinitron television tube appeared in the 1960s as the first
alternative to standard shadow mask tubes and has since been used in
most Sony monitors. Rather than using the standard dot triads,
aperture grill monitors use uninterrupted vertical stripes of
phosphors, alternating red, green, and blue across the width of the
screen. Masking is done by an aperture grill, which consists of a
series of very fine vertical wires covering the full width of the
tube, and corresponding to the phosphor stripes. In any given
vertical phosphor stripe, no mask separates individual pixels
vertically, so the top and bottom of each pixel must be delimited by
the accuracy of the scanning electron beam. The advantages of the
aperture grill are that it allows more electrons to pass than any
other masking method, which makes for a brighter, saturated,
high-contrast image on screen, and that the absence of hardcoded
vertical boundaries on pixels allows using any arbitrary vertical
resolution. A minor disadvantage is that the fine vertical wires that
comprise the grill are easily disturbed by mechanical shock such as
bumping the monitor, which results in a shimmering effect that may
take a few seconds to stabilize. Also, the vertical wires are
supported by one fine horizontal wire in 14-inch and smaller Sony
monitors, or two such wires (which divide the screen roughly in
thirds) on 15-inch and larger Sony monitors. These horizontal damper
wires cast a shadow that some users find objectionable, particularly
when they are visible on a light background. The Mitsubishi
Diamondtron tube, used in Mitsubishi's midrange and
high-end monitors, uses similar technology.

In early 2003, Sony announced its departure from the CRT monitor market and its intention to focus its efforts on flat-panel displays. As Sony winds down its CRT operations, it is unclear how much longer Sony will continue to produce Trinitron tubes for other monitor manufacturers. Existing orders and inventory already in the channel mean that new Trinitron-based monitors should remain available until late 2003, but if you want a Trinitron monitor, now is the time to get one.

The shadow mask is a perforated sheet of metal
whose holes correspond to dot triads, groups of
three colored phosphors, which may be arranged in various ways. Three
distinct variants of this masking technology are used.

The standard shadow mask is still used,
particularly in inexpensive generic monitors and in the
"value" models from name-brand
manufacturers. The standard shadow mask is a perforated sheet of
metal whose circular holes correspond to dot
triads, groups of three circular colored phosphor dots
arranged at the vertices of an equilateral triangle. The advantages
of the standard shadow mask are that it is inexpensive and provides a
reasonably sharp image. The disadvantage is that it blocks more
screen real estate than other methods, resulting in a noticeably
dimmer image, lower color saturation (muddy colors), and less
contrast. Also, its triangular pixel arrangement means that vertical
lines may show noticeable
"jaggies." Standard shadow mask
monitors are suitable for casual use, but are not the best choice for
intensive use.

The slotted mask, developed by NEC, is a hybrid
that combines the stability and sharpness of the standard shadow mask
with most of the brightness, contrast, and color saturation of the
aperture grill. The slotted mask is essentially a shadow mask in
which the small round holes are replaced by larger rectangular slots.
Like a standard shadow mask, the slotted mask uses discrete phosphor
trios, although they are arranged as rectangular stripes and cover
more of the screen surface. The slotted mask design is physically
more stable than an aperture grill, while the larger slots allow many
more electrons through than does a standard mask. The resulting
picture is brighter than a standard shadow mask monitor, but less so
than an aperture grill monitor.

The latest masking technology, Enhanced Dot
Pitch (EDP) from Hitachi, improves on the standard shadow
mask by increasing the size of the phosphor dots and changing their
geometry from an equilateral triangle to an isosceles triangle. The
larger phosphor dots result in a brighter image with more contrast
and color saturation, and the changed geometry provides a better
image that resolves finer detail. For example, a standard shadow mask
monitor with a 0.28 mm diagonal dot pitch actually uses a 0.14 mm
vertical pitch and a 0.24 mm horizontal pitch. A corresponding
Hitachi EDP monitor uses a 0.27 mm diagonal dot pitch with a 0.14 mm
vertical pitch and a 0.22 mm horizontal pitch. The smaller overall
dot pitch renders finer detail, and the smaller difference between
vertical and horizontal pitch results in subtle but very noticeable
differences in image quality.

16.1.1 Monitor Characteristics

Here are the important characteristics of monitors:

Screen size is specified in two ways. The

nominal size the size by which monitors
are advertised and referred tois the diagonal measurement of
the tube itself. However, the front bezel of the monitor conceals
part of the tube, making the usable size of the monitor less than
stated. Various consumer lawsuits have resulted in monitor
manufacturers also specifying the Viewable Image
Size (VIS), which is the portion of
the tube that is actually visible. Typically, VIS is an inch or so
less than nominal. For example, a nominal 17-inch monitor may have a
15.8-inch VIS. Small differences in VISe.g., 15.8-inch versus
16-inch make little practical difference. The smallest monitors
commonly available are 15-inch, although ViewSonic still produces a
14-inch model in their economy OptiQuest line. 17-inch remains the
most popular size, but 19-inch models are now so inexpensive that
they may soon overtake 17-inch models in unit sales. 20-inch and
larger monitors are still quite expensive, and are used primarily by
graphic artists and others who require huge displays. Table 16-1 lists monitor size and resolution combinations
that most people with 20/20 vision find optimum (++ is optimum; + is
suitable; - is generally unsuitable; is completely
unsuitable)

People with less-than-perfect vision often use the next size larger monitor (e.g., running 800 x 600 on a 17-inch monitor or 1024 x 768 on a 19-inch monitor), but we recommend instead using the optimum settings listed and configuring Windows and applications to display larger-than-normal fonts (e.g., set Display Properties to use the "Windows Standard (large)" or "Windows Standard (extra large)" scheme; set Internet Explorer font size to "Larger" or "Largest"; set Word to display text at 150% or 200%, and so on). Using high resolution provides finer-grained images, which are easier on the eyes.

Dot pitch

or stripe pitch
is measured in millimeters, and specifies the center-to-center
distance between the nearest neighboring phosphor dots or stripes of
the same color. Smaller pitch means a sharper image that resolves
finer detail. Unfortunately, dot pitch, which is used to describe
shadow mask monitors, cannot be compared directly to stripe pitch,
which is used to describe aperture grill monitors. For equivalent
resolution, stripe pitch must be about 90% of dot pitch. That is, a
0.28 mm dot pitch monitor has resolution similar to a 0.25 mm stripe
pitch monitor.

Maximum
resolution
specifies the maximum number of
pixels that the monitor can display, which is determined by the
physical number of pixels present on the face of the tube. The
maximum resolution of many low-end monitors is identical to the
optimum resolution for that monitor size. For example, 1024
x 768 is optimum for 17-inch monitors, so many low-end
17-inch monitors provide 1024 x 768 maximum resolution.
Conversely, midrange and high-end monitors may have maximum
resolutions higher than practically usable. For example, a high-end
17-inch monitor may support up to 1600 x 1200. There is no
real benefit to such extreme resolutions, although it can be useful
to have one step higher than optimum (e.g., 1280 x 1024 on
a 17-inch monitor or 1600 x 1200 on a 19-inch monitor)
available for occasional use for special purposes.

The synchronization
range specifies the bandwidth of the monitor, which
determines which combinations of resolution, refresh rate, and color
depth can be displayed. Synchronization range is specified as two
values:

The inverse of the time the monitor requires to display one full
screen. VSF (also called refresh rate) is
measured in Hz and specifies the number of times per second the
screen can be redrawn. To avoid screen flicker, the monitor should
support at least 70 Hz refresh at the selected resolution. Within
reason, higher refresh rates provide a more stable image, but rates
beyond 85 or 90 Hz are necessary only for specialized applications
such as medical imaging. Most monitors support a wide range of
refresh rates, from very low (e.g., 50 Hz) to very high (e.g., 120 to
160 Hz).

The inverse of the time the monitor requires to display one full scan
line. HSF is measured in KHz, and specifies the overall range of
bandwidths supported by the monitor. For example, a monitor running
1280 x 1024 at 85 Hz must display 1024 lines 85 times per
second, or 87,040 scan lines per second, or about 87 KHz. In fact,
some overhead is involved, so the actual HSF for such a monitor might
be 93.5 KHz.

Resolution and refresh rate are interrelated parts of the
synchronization range of an analog monitor. For a given resolution,
increasing the refresh rate increases the number of screens (and
accordingly the amount of data) that must be transferred each second.
Similarly, for a given refresh rate, increasing the resolution
increases the amount of data that must be transferred for each
screen. If you increase resolution or refresh rate, you may have to
decrease the other to stay within the HSF limit on total bandwidth.

Note that manufacturers often specify maximum resolution and maximum
refresh rate independently, without consideration for their
interrelatedness. For example, specifications for a 19-inch monitor
may promise 1600 x 1200 resolution and 160 Hz refresh.
Don't assume that means you can run 1600
x 1200 at 160 Hz. 160 Hz refresh may be supported only at
640 x 480 resolution; at 1600 x 1200, the
monitor may support only 70 Hz refresh.

Resolution and refresh rate alone determine the required bandwidth for an analog monitor. Color depth is immaterial because the color displayed for a given pixel is determined by the analog voltages present on the red, green, and blue lines at the time that pixel is processed. Therefore, at a given resolution and refresh rate, an analog monitor uses exactly the same bandwidth whether the color depth is set to 4, 8, 16, 24, or 32 bits because the video card converts the digital color data to analog signals before sending it to the monitor. For purely digital monitors, such as flat-panel units, greater color depth requires greater bandwidth because color information is conveyed to a digital monitor as a digital signal.

Monitors use one of three geometries
for the front viewing surface. Spherical tubes
are used in older monitors and some inexpensive current models. The
viewing surface is a section of a sphere, rounded both horizontally
and vertically, which results in apparent distortion at normal
viewing distances. This geometry keeps the center and corners of the
screen close to the same distance from the electron guns, allowing
the use of less-expensive shadow mask materials and
less-sophisticated and cheaper electronics.
Cylindrical tubes, first introduced with the
Sony Trinitron, use a section of a cylinder as the viewing surface,
and are vertically flat but horizontally rounded. This keeps the
distance from gun-to-center and gun-to-corners similar, while
reducing apparent distortion of the viewing area relative to a
spherical tube. Flat square tubes
(FSTs) are actually spherical in sections, but
from a sphere with a radius so large that they appear nearly flat.
The advantage to FST is that the image area is effectively flat,
minimizing viewing distortion. The disadvantage is that the electron
guns are much farther from the corners than the center, which in turn
demands a relatively costly Invar mask and more expensive electronics
to provide even coverage. Other than some
"value" models, all current
monitors, including Sony Trinitrons, use an FST.
Don't consider buying a monitor that
doesn't.

All monitors provide basic controlsbrightness, contrast,
horizontal/vertical image size, and centering. Better monitors
provide additional controls for such things as screen geometry
(pincushion and barrel distortion adjustments), color temperature,
and so on, as well as an onscreen display of settings. Changing
display settings such as resolution and refresh rate may also change
the size and position of the image. If you frequently change
resolution, look for a monitor that can store multiple settings so
that you will not have to readjust the monitor manually each time you
change display settings.

As 19-inch monitors become increasingly mainstream, monitor depth
also becomes an increasing problem. Historically, most monitors were
about as deep as their nominal screen size. With 15-inch monitors,
depth was usually not a problem. With 17-inch monitors, depth began
to be an issue, and with 19-inch monitors many people find that their
desks are not deep enough to accommodate them. Manufacturers have
responded by producing reduced-depth or
"short-neck" monitors. A short-neck
17-inch monitor is about the depth of a standard 15-inch monitor, and
a short-neck 19-inch monitor is about the depth of a standard 17-inch
monitor. That shorter neck involves some trade-offs, however.
Foremost is the fact that achieving that shorter depth requires
changing the deflection angle from the standard 90 degrees to 100 or
even 110 degrees. Increasing the deflection angle requires more
expensive electronics to compensate and results in reduced image
quality. In effect, you pay twice for a short-neck monitor because it
costs more and provides an inferior image.

16.1.2 Choosing a CRT Monitor

Use the following guidelines when
choosing a CRT monitor:

Remember that a monitor is a long-term purchase. Even with heavy use,
a high-quality monitor can be expected to last five years or more,
whereas inexpensive monitors may fail within a year or two. We have
several 17-inch monitors here that were purchased with one system and
have been moved to two or three successor systems over the years.
Good large monitors are inexpensive enough now that it makes sense to
buy for the long term.

Make sure the monitor is big enough, but not too big. Verify that
your desk or workstation furniture can accommodate the new monitor.
Many people have excitedly carried home a new 19-inch or 21-inch
monitor only to find that it literally won't fit
where it needs to. Check physical dimensions and weight carefully
before you buy. Large monitors commonly weigh 50 lbs. or more, and
some exceed 100 lbs. That said, if you find yourself debating between
buying one monitor and another that's the next size
up, go with the larger monitor. But note that if your decision is
between a low-end larger monitor and a high-end smaller one for about
the same price, you may well be happier with the smaller monitor. A
$200 17-inch monitor beats a $200 19-inch monitor every time.

Avoid reduced-depth monitors whenever possible. Space constraints may
force you to choose a short-neck model. Just be aware that you will
pay more for such a monitor, and its image quality will be lower.

Stick with good name brands and buy a midrange or higher model from
within that name brand. That doesn't guarantee that
you'll get a good monitor, but it does greatly
increase your chances. The monitor market is extremely competitive.
If two similar models differ greatly in price, the cheaper one likely
has significantly worse specs. If the specs appear similar, the maker
of the cheaper model has cut corners somewhere, whether in component
quality, construction quality, or warranty policies.

Deciding which are the "good" name
brands is a matter of spirited debate. Our opinion, which is shared
by many, is that until its departure from the CRT market in early
2003, Sony made the best monitors available, although they sold at a
premium. We now consider Hitachi, NEC-Mitsubishi, Samsung, and
ViewSonic to be the "Big Four"
monitor makers. Most of their monitors, particularly midrange and
better models, provide excellent image quality and are quite
reliable. Many people also think highly of EIZO/Nanao monitors.
You're likely to be happy with a monitor from any of
these manufacturers, although we confess that we use only Hitachi and
NEC-Mitsubishi monitors on our own primary systems.

Further down the ladder are "value"
brands such as Mag Innovision, Princeton, Optiquest, and others. Our
own experience with value brands, albeit limited, has not been good.
A Princeton monitor we bought died a month out of warranty, as did an
OEM Mag Innovision model that we bought bundled with a PC. Two Mag
Innovision monitors developed severe problems after less than two
years of use. In our experience, which covers many hundreds of
monitors purchased by employers and clients, the display quality of
the value-brand monitors is mediocre, and they tend not to last long.
The same is generally true of monitors bundled with systems. Although
there are exceptions, bundled monitors tend to be low-end models from
second- and third-tier makers. If you purchase a computer system from
a direct vendor, we recommend you order it without a monitor and
purchase a good monitor separately. You may be shocked by how little
you are credited for the monitor, but that indicates just how
inexpensive a monitor is typically bundled with systems. Also, make
sure to request that the shipping cost be reduced accordingly.
Although many direct vendors now offer free shipping, some still
charge $100 or so to ship the system and monitor. If you order only
the system unit, the shipping cost should be significantly lower, but
some vendors do not reduce the shipping cost unless you ask them to
do so.

Buy the monitor locally if possible. You may pay a bit more than you
would buying mail order, but, after shipping costs, not as much more
as it first appears. Monitors vary more between examples than other
computer components. Also, monitors are sometimes damaged in
shipping, often without any external evidence on the monitor itself
or even the box. Damaged monitors may arrive DOA, but more frequently
they have been jolted severely enough to cause display problems and
perhaps reduced service life, but not complete failure. That makes
the next point very important.

If possible, test the exact monitor you plan to buy (not a floor
sample) before you buy it. If you have a notebook computer, install
DisplayMate on it (the demo version is adequate and can be downloaded
from http://www.displaymate.com/demosl) and
use it to test the monitor. If you don't have a
notebook, take a copy of DisplayMate with you to the store and get
permission to run it on one of their machines. In return for the
higher price you're paying, ask the local store to
endorse the manufacturer's warrantythat is,
to agree that if the monitor fails, you can bring it back to the
store for a replacement rather than dealing with the hassles of
returning the monitor to the manufacturer. Mass merchandisers such as
Best Buy usually won't do this (they try to sell you
a service contract instead, which you shouldn't
buy), but small local computer stores may agree to endorse the
manufacturer's warranty. If the monitor has hidden
damage from rough handling during shipping, that damage will
ordinarily be apparent within a month or two of use, if not
immediately.

Most mainstream monitor manufacturers produce no 15-inch models
(there's no profit in them), and usually
threeGood, Better, and Bestmodels in 17, 19, and 21
inches. In general, the Good model from a first-tier maker
corresponds roughly in features, specifications, and price to the
Better or Best models from lower-tier makers. For casual use, choose
a Good model from a first-tier maker, most of which are very good
indeed. If you make heavier demands on your monitorsuch as
sitting in front of it eight hours a dayyou may find that the
Better model from a first-tier maker is the best choice. The Best
models from first-tier makers are usually overkill, although they may
be necessary if you use the monitor for CAD/CAM or other demanding
tasks. Best models often have generally useless features such as
extremely high resolutions and unnecessarily high refresh rates at
moderate resolutions. It's nice that a Best 17-inch
model can display 1600 x 1200 resolution, for example, but
unless you can float on thermals and dive on rabbits from a mile in
the air, that resolution is likely to be unusable. Similarly, a
17-inch monitor that supports 115 MHz refresh rates at 1024
x 768 is nice, but in practical terms offers no real
advantage over one that supports 85 or 90 MHz refresh.

Decide which makes and models to consider (but not the specific unit
you buy) based on specifications. Any monitor you consider should
provide at least the following:

Controls





Power; Degauss (if not automatic); Contrast; Brightness; Horizontal
Size; Horizontal Position; Vertical Size; Vertical Position;
Pincushion/Barrel Distortion Adjustment. Better monitors may add some
or all of the following: On-Screen Display; Focus; Individual Red,
Green, Blue Color Control (or Color Temperature); Tilt; Align; and
Rotate.




Warranty





Inexpensive monitors often have a
one-year parts and labor warranty (although 90-day warranties,
particularly on labor, are not unheard of). Better monitors usually
warrant the tube for two or three years (often excluding labor after
the first year) with one-year parts and labor on the remaining
components. Warranties on high-quality monitors may be for three
years parts and labor. In reality, the value of a long warranty on a
good monitor is less than it might seem. The few times
we've seen a good monitor fail,
it's either been soon after it was taken out of the
box or after many years of use. Conversely, a two- or three-year
warranty on an inexpensive monitor would be useful indeed because
such monitors frequently fail after a couple of years.
That's why you seldom find a good, long,
comprehensive warranty on a cheap monitor.




Other specifications vary according to monitor size. Remember that
shadow mask dot pitches are not directly comparable to aperture grill
stripe pitches. A 0.28 mm diagonal dot pitch corresponds roughly to a
0.25 mm stripe pitch. Also, not all dot pitches are specified in the
same manner. Some manufacturers specify the diagonal dot pitch.
Others, such as Hitachi, specify individual horizontal dot pitch and
vertical dot pitch. A monitor specified as having a 0.22 mm
horizontal dot pitch and 0.13/0.15 mm vertical dot pitch corresponds
roughly to a monitor with a 0.27 mm diagonal dot pitch. The minimum
specifications follow, with preferable values in parentheses:

15 inches





13.8-inch viewable image size (VIS); flat square tube (FST); 0.28 mm
diagonal dot pitch; maximum resolution 1024 x 768 (1280
x 1024); 75 Hz (85 Hz) refresh rate for standard 800
x 600 resolution. Automatically synchronize at 31 to 69
KHz (3180 KHz) horizontally and 55 to 120 Hz (50130 Hz)
vertically. As of July 2003, a high-quality, brand-name 15-inch
monitor can be purchased for $125.




17 inches





15.6-inch (15.8-inch) VIS; FST; 0.28 mm (0.27 mm) diagonal dot pitch;
maximum resolution 1280 x 1024 (1600 x 1200);
85 Hz (100 Hz) refresh rate for standard 1024 x 768
resolution, and 75 Hz (85 Hz) refresh rate at 1280 x 1024.
Automatically synchronize at 31 to 69 KHz (3195 KHz)
horizontally and 55 to 120 Hz (50160 Hz) vertically. As of
July 2003, a high-quality, brand-name 17-inch monitor can be
purchased for $140, only $15 or so more than a comparable 15-inch
model. That means buying a 15-inch model makes sense only if a
17-inch model is too large to fit the space available.




19 inches





17.8-inch (18.0-inch) VIS; FST; 0.28 mm (0.27 mm) diagonal dot pitch;
maximum resolution 1600 x 1200 (1920 x 1440);
85 Hz (100 Hz) refresh rate for standard 1280 x 1024
resolution, and 75 Hz (85 Hz) refresh rate at 1600 x 1200.
Automatically synchronize at 31 to 94 KHz (31110 KHz)
horizontally and 55 to 160 Hz (50160 Hz) vertically. As of
July 2003, a high-quality, brand-name 19-inch monitor can be
purchased for $250.




21 inches





19.8-inch (20.0-inch) VIS; FST; 0.28 mm (0.27 mm) diagonal dot pitch;
maximum resolution 1600 x 1200 (2048 x 1536);
85 Hz (100 Hz) refresh rate for standard 1600 x 1200
resolution, and 75 Hz (85 Hz) refresh rate at resolutions above 1600
x 1200. Automatically synchronize at 31 to 96 KHz
(31125 KHz) horizontally and 55 to 160 Hz (50160 Hz)
vertically. As of July 2003, a high-quality, brand-name 21-inch
monitor can be purchased for $600.




Choose the specific monitor you buy based on how it looks to you.
Comparing specifications helps narrow the list of candidates, but
nothing substitutes for actually looking at the image displayed by
the monitor. For example, monitors with Sony Trinitron tubes have one
or two fine horizontal internal wires whose shadows appear on screen.
Most people don't even notice the shadow, but some
find it intolerable.

Make sure the monitor has sufficient reserve brightness. Monitors dim
as they age, and one of the most common flaws in new monitors,
particularly those from second- and third-tier manufacturers, is
inadequate brightness. A monitor that is barely bright enough when
new may dim enough to become unusable after a year or two. A new
monitor should provide a good image with the brightness set no higher
than 50%.

It's worth expanding a bit on what we consider
"good" brand names because
that's one of the most frequent questions we get
from readers. When we talk to representatives of the various display
manufacturers, we always ask them the same question:
"Other than your own company, which two or three
companies make the best displays?" We hear the same
names over and over, and our own experiences and reports from readers
confirm which display makers are top-tier.

In the first edition of this book, the Big Four were (alphabetically)
Hitachi, Mitsubishi, NEC, and Sony. NEC and Mitsubishi subsequently
merged their monitor operations and two new names appeared on our
list. In the second edition, we listed the Big Four for CRT displays
as Hitachi, NEC/Mitsubishi, Sony, and ViewSonic, with Samsung close
on their heels. In early 2003, Sony announced its departure from the
CRT market. By that time, Samsung had demonstrated it was capable of
consistently producing top-notch CRT monitors, so Samsung now joins
Hitachi, NEC/Mitsubishi, and ViewSonic as a member of our Big Four.

Like all other component manufacturers, monitor makers have come
under increasing margin pressures. A few years ago, we felt safe in
recommending any monitor from a first-tier maker because those
companies refused to put their names on anything but top-notch
products. Alas, just as Gresham's Law says that bad
money drives out the good, the same holds true for CRT monitors. To
compete with cheap Pacific Rim monitors, first-tier makers have been
forced to make manufacturing cost reductions and other compromises.

Accordingly, low-end models from first-tier makers may be of lower
quality than they were in the past. The presence of a first-tier
maker's name plate still means that monitor is
likely to be of higher quality than a similar no-name monitor, but is
no longer a guarantee of top quality. Many first-tier monitors are
actually made in the same Pacific Rim plants that also produce
no-name junk, but don't read too much into that.
First-tier monitors are still differentiated by component quality and
the level of quality control they undergo. There is no question in
our minds that the first-tier monitors are easily worth the 10% to
20% price premium they command relative to lesser brands. In fact, we
think it is worth the extra cost to buy not just a first-tier
monitor, but a midrange first-tier monitor. We prefer Hitachi and
NEC/Mitsubishi models, including their entry-level models, but the
midrange and better Samsung and ViewSonic models are also
excellent.