Resolution: 720p and 1080p
Next, an HDTV must have a certain minimum resolution. Resolution
refers to the total number of pixels on the screen; a pixel is simply the colored
dot used to create the image. Resolution is expressed as the number of vertical lines of pixels times the number of horizontal lines of pixels. So, you’ll see
such specs as 1366 x 768 or 1920 x 1080. The higher the numbers, the sharper
To be considered an HDTV, a set must have at least 720 horizontal lines
of resolution. A new generation of HDTVs has at least 1,080 horizontal lines,
which works out to more than 2 million total pixels. These are called 1080p
(or “full HD”). Both 720p and 1080p screens will produce an excellent image,
but 1080p will typically cost more.
Here are some other terms you’ll come across when researching HDTVs.
Refresh rate. This is the number of times a display’s image is repainted or refreshed per second. The refresh rate is expressed in hertz (Hz), so a refresh rate
of 60 Hz means the image is refreshed 60 times in a second. The higher the rate,
the better. New technology features a “frame rate conversion” process (
available in 120 Hz) for superior fast-motion image processing.
Contrast ratio. This refers to the difference between the “whitest” image the
set can produce divided by the “blackest” image. Typically, the higher the contrast ratio, the better the black levels, but let your eyes be the ultimate judge.
Progressive and interlaced. You’ll see references to 720p and 1080i signals.
The letters refer to progressive and interlaced—the way the program is presented on the screen (see box below). The latest TVs can handle both signals.
LCD, plasma and rear-projection HDTVs display images progressively.
THE ARGUMENT FOR 1080P
Should you opt for an HDTV with a resolution
of 1080p, or go with a 720p model? There
are some compelling reasons to choose a
The “1080” refers to the number of horizontal
lines of pixels filling the screen. The more
lines, the higher the resolution. A 1080p
screen has 1,080 horizontal lines of pixels
and typically 1,920 vertical lines of pixels. This
resolution is referred to as 1920 x 1080.
A “720p” HDTV has at least 720 lines of
resolution, and typically 1,024 to 1,366
vertical lines. So a 1080p HDTV has more
pixels than a 720p HDTV, and more pixels
equates to a higher resolution.
The other advantage is how 1080p works.
Not long ago, the best tube TVs used a 1080i
process. The “ i” indicates that the images
were conveyed in an interlaced format: The
images get painted on the screen sequentially,
with the odd-numbered lines appearing first,
followed by the even-numbered lines, all within
one-thirtieth of a second. This method can produce the kind of flickering seen on older TVs.
In comparison, 1080p systems use a progres-sive-scan format. All of the lines of resolution
are sent sequentially in a single pass, making
for a smoother, cleaner image. This is especially apparent when viewing sporting events
and other fast-moving situations.
The new Blu-ray Disc format produces images
in the 1080p format. When you watch movies
in this new format with a 1080p set, you’ll be
getting the sharpest resolution available in the
HD world today.
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Today’s Panasonic plasmas are rated to last
100,000 hours before reaching half brightness.
Based upon the U.S. average daily viewing
time of six and a half hours, Panasonic 1080p
plasma HDTVs could on average take more
than 42 years before they reach half of their
original brightness level.
Panasonic DVD home cinema products
feature a 1080p up-conversion function that
converts standard-definition images from DVD
sources to near-high-definition images. These
up-converted signals draw out the maximum
performance of an HDMI-compatible 1080p
HDTV, offering vivid, sharp and exceptionally
detailed high-resolution ima ges to enj oy.