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Satellite TV
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Components:
The Receiver
The
satellite TV home receiver does four tasks:
- It de-scrambles the encrypted in-coming
TV signal. In order to unlock
the signal, the receiver needs the proper decoder chip for
that programming package. The provider can communicate with
the chip, via the satellite signal, to make necessary
adjustments to its decoding programs. The provider may
occasionally send signals that disrupt illegal
de-scramblers, as an electronic counter measure (ECM)
against illegal users.
- It takes the digital MPEG-2 signal and converts it into
a format that a standard television can recognize.
In the United States, receivers convert the digital signal
to the analog NTSC format or a digital TV format. Some dish
antenna and receiver setups can
also output an HDTV (720p, 1080i) signal.
- It extracts the individual channels from the larger
satellite signal. When you change the channel on the
receiver, it sends just the signal for that channel to your
TV. Generally you can't
watch two different programs on two TVs hooked up to the
same receiver (unless you have a multi-tuner receiver). In order to do
this, you may need to get an
additional receiver.
- It keeps track of pay-per-view programs and periodically
phones a computer at the provider's headquarters to
communicate billing information.
Receivers have a number of other features as well. They
pick up a programming schedule signal from the provider and
present this information in an onscreen programming guide (EPG).
Many receivers have parental lock-out options, and some have
built-in digital
video recorders (DVR), which let you pause live
television or record it on a hard disk drive (HDD). While digital broadcast satellite service is still lacking
some of the basic features of conventional cable (the ability
to easily split signals between different TVs and VCRs,
for example), its high-quality picture, varied programming
selection and extended service areas make it a good
alternative for some.
Columbia ISA
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