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Frequently Asked Questions
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. Another feature of digital television is digital surround sound using Dolby Digital technology,
which is the same technology used to produce the sound you hear in movie theaters.
What Is Standard-Defi nition Television?
Standard-defi nition television (SDTV) is a television system that uses a resolution that is not
considered to be high-defi nition television (HDTV 720p, 1080i, and 1080p). The two common
SDTV signal types are 576i, with 576 interlaced lines of resolution, derived from the European-
developed PAL and SECAM systems; and 480i, with 480 interlaced lines of resolution, based on the
American National Television System Committee (NTSC) system.
In North America, digital SDTV is broadcast in the same 4:3 aspect ratio as NTSC signals. In other
parts of the world that used the PAL or SECAM color systems, standard-defi nition television is now
usually shown with a 16:9 aspect ratio.
What Is High-Defi nition Television?
High-Defi nition Television (HDTV) is a high-quality video standard developed to replace older video
formats often referred to as SDTV (Standard-defi nition television). While HDTV’s video quality is
one of the most noticeable improvements over SDTV, HDTV includes a number of other important
improvements as well.
First of all instead of an analog signal, used by traditional NTSC broadcasts, HDTV is always digital.
This eliminates analog interference caused be electrical currents and magnetic fi elds. Secondly, HDTV
uses a diff erent aspect ratio than SDTV. While previous broadcasts used a 4:3 ratio, HDTV uses a ratio
of 16:9. This wider aspect ratio more closely emulates how humans see the world, making the image
appear more realistic. This ratio is also better for watching widescreen movies, which are recorded in
widescreen for the same reason. HDTV signals are either 720p, 1080i or 1080p.
Are Local TV Stations or Other Programmers Broadcasting in HDTV?
Many local TV stations and programmers 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-defi nition channels. Most stations and programmers, once
they begin broadcasting in digital, are off ering HD content from their parent network (for example,
CBS, ABC, NBC, Fox, and PBS). Contact your service provider for more information.
Why Aren’t All of the Shows that I Watch in High-Defi nition?
A high-defi nition program must originate in HD format and be broadcast in HD format. Having an
HDTV system does not mean that everything you watch will be viewed in high-defi nition. Getting the
signal from a digital source also does not mean it is high-defi nition.
What Is HDMI and Does it Support Dolby Digital 5.1 Audio?
The High-Defi nition Multimedia Interface (HDMI) is an uncompressed, all-digital audio/video
interface. The Dolby Digital audio format that provides up to 5.1 separate channels of surround
sound, and is the standard used for DVD-Video. HDMI supports standard, enhanced, or high-
defi nition video, plus multi-channel digital audio, such as Dolby Digital audio, on a single cable.
