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channel, at sampling rates of 48 kHz for Blu-ray Disc, and 44.1 kHz and 48
kHz for HD DVD, with a resolution up to 24-bits.
B) HD DVD DTS Sub Audio
An optional format for HD DVD discs, considered of high quality using low bit
rate audio; designed for network streaming, broadcast and Internet
applications. Is a two-channel (2.0) scalable format, using from 64 to 192
kbps data rates, and sampling rates from 8 kHz to 96 kHz with 24-bits
resolution.
DTV (Digital Television): The DTV standard is composed of 18 digital formats
grouped into two levels of quality, as approved by the ATSC (American Television
Systems Committee) in 1995:
1) SD: Standard definition, 480i/p visible vertical resolution lines, with up to 704
total pixels of horizontal resolution, aspect ratio in 4x3 or widescreen 16x9, and
2) HD: High definition, 720p and 1080i/p visible vertical resolution lines, with
respectively 1280 and 1920 total pixels of horizontal resolution, in widescreen 16x9
aspect ratio.
The FCC actually let manufacturers implement compatible DTV tuners with the ability
to receive/decode the formats without imposing TVs to display the formats at their
original resolutions; the tuners would generally convert the signals to 480p, 720p,
and 1080i, to match the native format of most monitors. Later in 2000, the
Consumer Electronics Association (CEA) created another level in between SD and
HD: ED (enhanced), which promoted the 480p format from SD to ED, among other
changes (see 810i).
The current NTSC over-the-air (OTA) TV system is 480i analog (actually 525i with
480i visible lines) and is interlaced. Digital satellite and digital cable are equivalent
to digital SD but they are also transmitting some channels in HD. To facilitate the
transition broadcasters were given one extra channel slot from the FCC for the
simultaneous broadcasting of the analog and digital versions of their programming.
It is a large investment for stations to build a DTV facility with new cameras,
equipment, etc. When DTV is fully implemented, broadcasters have to return one of
the two channels, analog over-the-air broadcasting will stop, and current TVs, VCRs,
Tivos, and any other equipment with analog tuners would stop tuning as well.
The DTV system implementation is mandatory; HDTV is optional. The
implementation of DTV was originally planned by 2007, but the deadline has been
conditioned to when 85% of the US population can receive DTV signals, discussions
were held in 2004 to determine if cable and satellite subscribers should be
considered as part of the 85%, cable itself covers about 70% of the US population.
In February 1, 2006, an extension to the deadline was approved, the new date for
the discontinuation of analog transmissions is February 17, 2009, and the deadline is
not conditioned to a percent of DTV reception by households per market as
originally, it is a hard date.
DTV Tuners: The ATSC (Advanced Television Systems Committee) selected 8VSB
as the digital television standard for terrestrial (over-the-air) broadcast of HD signals
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