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Frequently Asked Questions About HDTV and Digital TV
What is Digital Television?
Digital television (DTV) is a huge leap forward in television technology compared to analog television that
has been widely available since the 1940s. DTV is delivered and displayed using digital encoding, similar to
the way a PC operates. By using digital technology, there is no variation in picture and sound quality from the
origination point until it is displayed on your television. You always receive a high-quality picture without the
wavy lines or static you might sometimes get from a weak analog signal.
Because DTV receives and displays digital images that contain many times more picture elements (pixels –
the small dots that make up the color image on your screen) than standard analog television, you can get a
sharper on-screen image than with analog. Additionally, DTV supports CD-quality sound. DTV includes SDTV
(Standard Definition Television), EDTV (Enhanced Definition Television), and HDTV (High-Definition Television).
That means that all HDTV is digital, but not all digital TV is high-definition. A high-definition program must
originate in HD format and be broadcast in HD format. Simply having an HDTV system does not mean that
everything you watch will be in high-definition.
What is Standard-Definition Television?
Standard-definition television (SDTV) is basic digital television programming delivered by cable. Typically, the
SDTV screen is the same, nearly square shape as an analog television screen. Digital images on an SDTV set
are crisp and clear—noticeably better than on a standard analog television set using an antenna to receive
over-the-air signals or on a cable-ready TV connected without a digital set-top.
What is High-Definition Television?
High-definition television (HDTV) is a completely new way to send and receive television broadcast signals.
HDTV images are made up of pixels that are much smaller and closer together than those used in standard
analog television, and there are millions of them. Thus, HDTV can display five to six times the detail of analog
television to deliver picture quality that is much more realistic, dimensional, and precise. SDTV programs can
be viewed on an HDTV. Another feature of HDTV is digital surround sound using Dolby Digital®, which is the
same technology used to produce the sound you hear in movie theaters.
Are Local TV Stations Broadcasting in HDTV?
Many local TV stations are transmitting digital signals. However, transmitting a digital signal does not mean
transmitting an HDTV signal. Some stations are using the new bandwidth to broadcast several standard-
definition channels. Most stations, once they begin broadcasting in digital, are offering HD content from their
parent network (for example, CBS, ABC, NBC, Fox, WB, UPN, and PBS).
Why Are Some HDTVs 4:3 Aspect Ratio and Others 16:9?
The aspect ratios differ because television manufacturers build both standard-screen and wide-screen
HDTVs to appeal to consumer viewing preferences.
The two aspect ratios are as follows:
•
On wide-screen (16:9) HDTVs, the programming is displayed on the full screen.
•
On standard-screen (4:3) HDTVs, the programming is displayed in letterbox format in the middle of the
screen. (There are bars surrounding the picture.)
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