Transcript Xilinx XC4000 FPGA devices - Mahanakorn University of

Chapter IV
DTV&DVB
By Theerayod Wiangtong, PhD., DIC
Mahanakorn University of Technology
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Part I: Shifting from Analog to
Digital Television System
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History of Television
• First Monochrome Broadcast of Electronic Television in
England, 1936
• Introduction of Color Television based on the three primary
colors, ~1968
• Digital Television is the next big revolution in television,
~2000-2006
– multimedia standards converge under the digiTV standards
– services can be experienced whenever, and wherever the
consumer wants
– enhanced quality, multiplication of channels, interactivitiy, access
to Internet services
– interacting with content is the major issue
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Color TV systems
• Analog Color TV systems: Video Production,
Transmission, and Reception.
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Why not using RGB directly?
• R,G,B components are correlated
– Transmitting R,G,B components separately is
redundant
– More efficient use of bandwidth is desired
• RGB->YC1C2 transformation
– Decorrelating: Y,C1,C2 are uncorrelated
– C1 and C2 require lower bandwidth
– Y (luminance) component can be received by B/W TV
sets
Color transformation is a compromised solution, but the ultimate one
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Why YUV?
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Color Video Signal
White
level
100
Phase=241°
Phase=61°
80
Phase=103°
60
Phase=347°
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Color burst
Phase=0°
Phase=167°
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IRE
Black
level
Blank
level
Phase=283°
Sync
level
Backporch
- 40
Blanking Interval
Video
Carrier
Black
Blue
Red
Magenta
Green
Cyan
9 cycles
Yellow
-20
W
hit
e
0
Visible Line Interval
Color
Audio
Sub-Carrier Sub-Carrier
Cr BW = 0.6 MHz
Cb BW = 0.6 MHz
Cr BW = 1.3 MHz
Cb BW = 0.6 MHz
0
7
3.58 MHz
4.5 MHz
Analog Video Standards
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Analog Video Standards Ch’s
Parameter
NTSC
PAL
SECAM
Field Rate
59.94
50
50
Line Number/Frame
525
625
625
Line Rate (Line/s)
15,750
15,625
15,625
Image Aspect Ratio
4:3
4:3
4:3
Color Coordinate
YIQ
YUV
YDbDr
Luminance Bandwidth (MHz)
4.2
5.0,5.5
6.0
Chrominance Bandwidth (MHz)
1.5(I),0.5(Q)
1.3(U,V)
1.0(Db,Dr)
Color Subcarrier (MHz)
3.58
4.43
4.25(Db),4.41(Dr)
Color modulation
QAM
QAM
FM
Audio Subcarrier (MHz)
4.5
5.5,6.0
6.5
Composite Signal Bandwidth (MHz)
6.0
8.0,8.5
8.0
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Why Digital Television?
• Revolutionary Change
– Existing TV sets will not receive it
– Totally separate physical plant
4:3 Aspect Ratio
16:9 Aspect Ratio
• Digital carrier can transmit any digital
content
– The television content is sent as data
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Not great to begin with…
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Getting worse…
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Still worse…
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Yuck!
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The Digital TV Experience
• Improved picture quality
– Analog with weaker and weaker signals
– Digital with weaker and weaker signals
• Program guide information
– Display depends on TV or receiver
• Virtual channel numbers
• Multicasting
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Picture stays like this until…
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it’s right on the borderline…
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and then it’s gone!
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Digital Television (DTV)
•Three major standards for DTV: DVB (Europe), ATSC
(U.S), and ISDB (Japan)
•Analog Switch-off: (e.g. Netherlands (Dec 06), Belgium
(Jan 2007), USA (Feb 09))
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Comparison of Classic Analogue
and Modern Digital TV
• Digital TV from the technological viewpoint
enables:
– Higher video quality (e.g. high-definition-TV)
– Higher audio quality (e.g. 5.1 Dolby surround)
– TV equipment is equipped with small-sized computer alike software
– Internet connection on TV-equipment
– New content forms as known from the Internet (e.g.
MPEG-4 support, HTML)
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Examples of Digital TV ValueAdded Services - Overview
•
•
•
•
•
•
•
Electronic Program Guide
(EPG)
Information Portal
Pay-per-View (PpV)
Video-on-Demand (VoD)
Education
Shopping
Games
• Standard Internet Services
• Communication
• Community Services
• Government
• Health
• Finance and Banking
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DTV Formats
•
HDTV - High Definition TV
– 720p vertical scanning lines or
higher
– 1920x1080 is true HDTV
– 16:9 aspect ratio
•
EDTV - Enhanced Definition TV
– 480p vertical scanning lines or
higher
– Aspect ratio not specified
•
SDTV - Standard Definition TV
– Digital reception but can be less
than EDTV resolution
– Aspect ratio not specified
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DTV Broadcasting
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ATSC (USA)
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DVB (Europe)
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ISDB (Japan)
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Around the World
Lähde: DVB
MPEG-2 Data Streaming Type
MPEG-2 Program Stream
• Combines one or more Packetised Elementary
Streams (PES), which have a common time-base,
into a single stream
• Designed for use in relatively error-free
environments (e.g. digital storage) and suitable for
applications which may involve software processing
• Program stream packets may be of variable and
relatively great length
MPEG-2 Transport Stream
• Combines one or more Packetised Elementary
Streams (PES) with one or more independent time
bases into a single stream (sometimes called
multiplex)
• Designed for use in environments where errors are
likely, such as transmission in lossy or noisy media
• The transport stream is made of packets with fixed
length of 188 bytes
System Layers
layered system with header/descriptors
996 Mb/s
Multiple Picture Formats
and Frame Rates
Picture 1920 x 1080 @60I
Layer
Compression
Layer
Data
Headers
Motion
Vectors
Chroma and Luma
DCT Coefficients
MPEG-2 video
and Dolby AC-3
compression
syntax
Variable Length Codes
Flexible delivery of data
and future extensibility
Packet Headers
Transport
Layer
Video packet
Audio packet
Video packet
Aux data
MPEG-2 packets
Terrestrial
Transmission
Layer
19.3 Mb/s
31
6 MHz
Source:Sarnoff Corporation
Different Programs
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PES to PT
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The Transport Stream Packet
Different Resolution
• DTV sends a stream of digital packets
HDTV
SDTV
Data
Null
• >103,000 packets per second (188
bits/packet)
– The packet header identifies the packet as
High Definition TV, SDTV, MP3 files, Web
pages, Databases or other content
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Streaming data
• Digital Television is a 19.39
Mbps “pipe”
• MPEG-2 native transport,
but IP can be encapsulated
• Bandwidth required for
DTV varies from 3.5 Mbps
to 19.39 Mbps
• Data can use opportunistic
to 15.9 Mbps
• Rates will improve over
time
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Bandwidth
• Digital Television uses the same RF propagation
as analog TV
– Same Radio Shack antenna will work
Digital Station
Analog Station
Ch. 6
Ch. 7
Ch. 8
Ch. 9
Ch. 10
Ch. 11
Ch. 12
6 Mhz
6 Mhz
6 Mhz
6 Mhz
6 Mhz
6 Mhz
6 Mhz
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How Does it Work?
19.4
Mbps
High Definition
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How Does it Work?
Standard Definition
19.4
Mbps
High Definition
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How Does it Work?
Multicast
Program 5
Program 4
Program 3
19.4
Mbps
Program 2
Program 1
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How Does it Work?
Data
Standard Definition
19.4
Mbps
High Definition
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Part II: Broadcasting
Studio
Studio
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DVB History
DVB Standard
• DVB uses the MPEG-2 Transport Stream to carry
it’s data
• DVB has added some features in the MPEG-2
standard (the MPEG standard had a door open for
future additions to the standard)
• Can deliver to the home almost anything that can be
digitized:
– High Definition Television (HDTV)
– Standard Definition Television (PAL / NTSC, SECAM)
– New broadband multimedia data and interactive services
DVB Sub-standards
There are several sub-standards of the DVB standard
•DVB-S (Satellite) – using QPSK – 40 Mb/s
•DVB-T (Terrestrial) – using OFDM – 24 Mb/s
•DVB-C (Cable) – using QAM – 50 Mb/s
•DVB-IPI (IPTV) – IP-based NW)
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DVB Advantages
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DVB Advantages
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DVB Disadvantages
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DVB Block Diagram
To encode and compress television video stream
Raw PAL TV signal would need 864 MBit/s!
MPEG-2 reduces this to 2–8 MBit/s
Packetized Elementary Streams (PES)
Different data streams of each single TV channel
Max. 64 KByte per packet
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DVB Block Diagram
Forward Error Correction (FEC) with Reed Solomon Code
•Adds 16 Bytes to 188 Byte transport stream packets
•Enables receiver to correct up to 8 destroyed bytes
•Reed Solomon Decoder can set “Transport Error Indicator” to signal error condition
to upper layers
•Disadvantage: delays signal due to time necessary for FEC calculation and
error correction
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Receiver Deployed
DVB-S2 – Improvement over DVB-S.
Significant improvement to satellite
transmission efficiency
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Quality of DVB-S/-C vs. DVB-T
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Design goal of DVB-S
• Using single 38 Mbps Satellite transponder :
DVB-S can provide
– 4 – 8 Standard TV channels (depending on quality)
– 2 High Definition TV (HDTV) channels
– 150 Radio programs
– 550 ISDN-style data channels at 64 kbps
– A variety of other high and low rate data services
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DVB-S
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DVB-S Modulation
DVB-S2
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DVB-RCS
Typical remote SIT
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