This document provides an overview of high definition television (HDTV) including its history, technology advancements, standards, specifications, components, timeline for adoption, applications, and status. It discusses how HDTV provides higher resolution and wider pictures compared to traditional television standards through advances like progressive scanning. The document also compares HDTV specifications to existing NTSC standards and includes visual comparisons of picture quality between current TVs and HDTVs.
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History
First began in 60’s at NHK, the
Japan Broadcasting Corporation.
Many different formats were
developed in US
In Feb 1993, FCC suggested to form
an alliance that would eventually
create the best possible system
In May 1993, Grand Alliance formed
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Current TV Standards
TV Standards NTSC PAL SECAM
Regions U.S. Asia, Europe,
South America
France
Channel Bandwidth 6MHz 8MHz 8MHz
Aspect ratio 4:3 4:3 4:3
NTSC: National Television Systems Committee
PAL: Phase Alternation Line
SECAM: Séquential Couleur Avec Mèmoire
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HDTV and NTSC Specifications
HDTV USA NTSC
Aspect ratio 16:9 4:3
Largest frame rate 60 frames/sec 30 frames/sec
Vertical refresh rate 60 Hz 60 Hz
Highest resolution 1080 lines 525 lines
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Additional Specs of HDTV
System outlined in the ATSC standard is based on the
MPEG-2 Main Profile
Video formats span the range of Main Level to High Level
Audio Compression is based on the Dolby AC-3 system
with sampling rate 48kHz and perceptually coded
5.1 Channels of surround-sound audio
Transport subsystem based on MPEG-2 Transport Stream
Packets consist of 188 bytes
RF subsystem is 8 VSB
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Components of HDTV systems
Display
Processor
Audio
Decoder
Image
Decoder
Demodulator Demultiplexer
Decoded
video
signals
Decoded
audio
signals
Display
format
video
signals
audio
signals
digital
signals
analog
carrier
+
digital
signals
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Timeline of HDTV
November 1998: HDTV transmissions begin at 27 stations in the
top 10 markets
May 1999: network affiliates in the top 10 markets must show at
least 50% digital programming
November 1999: digital broadcasts in the next 20 largest markets
May 2002: remaining commercial stations must convert
2003: public stations must convert to digital broadcasts
2004: stations must simulcast at least 75% of their analog
programming on HDTV
2005: stations must simulcast 100% of their analog programming
2006: stations relinquish their current analog spectrum
NTSC TV sets will no longer be able to pick up broadcast signals
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Current Status
18 digital TV formats are approved
by FCC
More than 27 digital channels being
broadcast by ABC, CBS, FOX, NBC
DirecTV has one HDTV channel
Unity Motion is broadcasting three
HDTV channels
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Hardware Requirement
Digital Decoder
– converts digital signals to analog
– allow current TV set to work
Digital-Ready TV set
– Wide-screen format
– progressive scanning
HDTV set
– Wide-screen format
– can receive 18 digital input format
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Conclusion
The history, standard, application of
HDTV have been introduced
HDTV has higher resolution, uses
progressive scanning and wider
screen leading to better perspective
on the scene
HDTV has a promising future and is
believed to replace NTSC in near
future
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Q:Analog bandwidth of HDTV signals?
HDTV image size of 1050 by 600 at 30
frames per sec, the bandwidth required to
carry that image quality using the analog
transmission system is 18MHz. However, it
will require more bandwidth to transmit it in
digital format.
With the MPEG-2 compression, the bit rate
is compressed from more than 1 Gbps to
about 20 Mbps, which transmit digitally only
require bandwidth 6MHz
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Q:Aspect ratio of movies vs HDTV?
Aspect ratio of HDTV is 16:9. However,
aspect ratio of movies has many different
formats:
“Movies are always shot so they can be displayed in
several aspect ratios at different types of movie theaters,
from the shoebox-sized foreign movie houses to the ultra
big screen Star Wars jobs.” ----- Franco Vitaliano
http://www.vxm.com/21R.107.html
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Q:Copyright protection for HDTV?
We do not find any group which mention
about copyright protection for HDTV.
Currently, broadcast stations sometimes put
their logo on the right bottom corner of their
analog broadcast programs. We think that
this method can still be used as one way for
protecting copyright for HDTV.