Why The
Right now the
To transmit a signal for HDTV can require up to five times as much data as a
standard television signal. In the frequency range allocated for television
broadcast there is not enough open bandwidth to transmit that much data via an
analog signal. To accommodate more HDTV transmissions more and more transmissions
in the
It is possible to greatly increase the amount of compression applied to the
data within the signal with digital transmissions as compared to analog
transmissions. Digital transmissions use the Mpeg 2 standard of compression;
with this compression technology it is possible to compress the data as much as
55 to 1. The standard is what is known as a "lossy" standard, which
does mean that there is some quality lost. However the final quality is still
far superior to the NTSC standard currently used for analog television
transmissions. The Mpeg 2 standard is already the standard compression used for
DVD's and digital satellite stations.
The final quality of a digital signal is far superior to an analog signal for
several reasons. First as stated earlier the Mpeg 2 is a superior technology to
the NTSC and creates a better product before it is transmitted. Secondly
digital signals do not allow for any loss of quality during the transmission.
Analog transmissions are transmitted as a wave signal, which allows for signal
degradation during the transmission. Digital signals are a series of 1's and
0's and only require that the signal be strong enough to be received. As long
as the signal is received then the data will be a perfect reproduction of the
data that was originally transmitted. With an analog signal though as the
signal power decreases so does the quality. The weaker the signal the lower the
quality of the image that is reproduced by the television receiver at the other
end of the signal. This is what causes static and "snow" when you
watch anything broadcast with an analog signal.
Because of the improved quality and improved flexibility in broadcast format
there are many good reasons for the US to make the switch to digital. Over the
next several years more and more stations will change to a digital signal
instead of analog. Soon there will be few if any stations still broadcasting an
analog signal.
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About the Author
Steve Welker Owner & Operator of http://www.dw-refurbished-television.com

