Digital Terrestrial Broadcasting Systems
Nov 08, 2014
Digital Terrestrial Broadcasting Systems
Digital Terrestrial Broadcasting Systems
Dr. A. Kholod (FM/GF) 2
Goals
Introduction DRM DAB DVB Conclusion
• Basic understanding of digital broadcasting• General description of DRM, DAB, DVB• Current developments in Switzerland
Dr. A. Kholod (FM/GF) 3
• at each time (t) – a certain exact signal level (y)
• amplitude (y) vs time (t) is a continuous function
• world around us is analogue
Analogue & digital - what is it ?
t
y
01234
Digital signal
• changes of y - only at determined moments
• amplitude (y) vs time (t) is a discrete function
• computer world is digital
t
y
01234
0 1 2 3 4 4 4 1 0 0 0 1 2 2 2
Analogue signal (music)
Introduction DRM DAB DVB Conclusion
Dr. A. Kholod (FM/GF) 4
digital signal receiveddigital signal received
Why digital transmission ?analogue signal sentanalogue signal sent
added noiseadded noise+
=
analogue signal receivedanalogue signal received
digital signal sentdigital signal sent
added noiseadded noise+
=
Introduction DRM DAB DVB Conclusion
“0”“0”
“1”“1”
“?”“?”
Dr. A. Kholod (FM/GF) 5
System failure characteristic
edge of service
area
edge of service
area
DistanceDistance FarFarNearNear
Qu
alit
yQ
ual
ity
PoorPoor
ExcellentExcellent
AnalogueAnalogue
DigitalDigital
Introduction DRM DAB DVB Conclusion
Dr. A. Kholod (FM/GF) 6
• Radio
Digital broadcasting technologies
• Television
- FM: UKW
- AM: LW / MW / SW
Introduction DRM DAB DVB Conclusion
Dr. A. Kholod (FM/GF) 7
• Is being developed to replace analogue LW, MF and SW radio below 30 MHz
• Designed as a flexible system able to overcome adverse propagation conditions – deep and long fades, echoes and multipath
• Has a variety of audio and channel coding options and modulation schemes to copy with different channel bandwidth requirements
• Is unidirectional → return channel is not possible• Data rate is limited (16 kbs) → CD sound quality is not
reached
Digital Radio Mondiale
Introduction DRM DAB DVB Conclusion
Dr. A. Kholod (FM/GF) 8
DRM vs analogue quality
Introduction DRM DAB DVB Conclusion
• AM
• DRM
Listen
Listen
Dr. A. Kholod (FM/GF) 9
RAMPISHAM
SINES
ORFORDNESS
KOTKA
BOCKHAGEN
ERLANGEN
LIMASSOL
• There is no DRM stations operation on the territory of Switzerland
• Reception of signals from foreign stations is possible
DRM in Switzerland
Introduction DRM DAB DVB Conclusion
Dr. A. Kholod (FM/GF) 10
• Supersedes FM• Gives spectrum efficiency • 1.5 Mbs channel → provides CD sound quality• Allows transmission of data (multimedia) services
(e.g. traffic information, stock market information, programme details, etc)
• Uses OFDM modulation → very robust
Digital Audio Broadcasting
Introduction DRM DAB DVB Conclusion
Dr. A. Kholod (FM/GF) 11
Introduction DRM DAB DVB Conclusion
• Something of a sleeping beauty since 2000- Low public acceptance of T-DAB: expensive and
limited receivers, no portable and handheld receivers in 2000, copying of FM service
• FM is exhausted- FM transmission networks can not be further
expanded without a significant loss of quality• DAB receivers became available
- Low price receivers for portable reception
• Strict non-ionising radiation requirements in CH- Demand for new distribution technologies that
produce less electromagnetic radiation
DAB in Switzerland
Dr. A. Kholod (FM/GF) 12
Introduction DRM DAB DVB Conclusion
• Portable indoor reception
20002005
2000: 60 %2005: 70 %2008: 80 %
national coverage
2006
2007
2008
2009
DAB in Switzerland
Dr. A. Kholod (FM/GF) 13
• Deutschschweiz– DRS 1 (UKW)– DRS 2 (UKW)– DRS 3 (UKW)– Virus– Musigwälle 531 (MW)– La Première (UKW)– Rete Uno (UKW)– Radio Rumantsch– Radio Swiss Jazz– Radio Swiss Pop– Radio Swiss Classic
• Suisse Romande– La Première (UKW)– Espace 2 (UKW)– Couleur 3 (UKW)– Option Musique (MW)– DRS 1 (UKW)– Rete Uno (UKW)– Radio Rumantsch– Radio Swiss Jazz– Radio Swiss Pop– Radio Swiss Classic
DAB programs
Introduction DRM DAB DVB Conclusion
Dr. A. Kholod (FM/GF) 14
Introduction DRM DAB DVB Conclusion
Television Transmission Paths
TTERRESTRIAL
terrestrialterrestrial
satellitesatellite
SSATELLITE
cablecableC
CABLE
In progress
Ok
Ok
Dr. A. Kholod (FM/GF) 15
• Replaces current analogue television service• Provides new concepts: single frequency networks• Gives better spectrum efficiency• Can carry much more than just TV (electronic program
guide; internet service; multimedia data, news, weather; interactive services; software updates, games)
Terrestrial Digital Video Broadcasting
Introduction DRM DAB DVB Conclusion
Dr. A. Kholod (FM/GF) 16
Different reception modes
fixedoutdoorfixedoutdoor portable
indoorportable
indoor
mobilemobile
TTERRESTRIAL
Introduction DRM DAB DVB Conclusion
Dr. A. Kholod (FM/GF) 17
Resistance to interference
CC
II
50 dB50 dB40 dB40 dB35 dB35 dB30 dB30 dB25 dB25 dB20 dB20 dB
IIIIIIIIII
FieldStrengthFieldStrength
• Analogue receptionT
TERRESTRIAL
Introduction DRM DAB DVB Conclusion
Dr. A. Kholod (FM/GF) 18
CC
25 dB25 dB
II
20 dB20 dB
II
FieldStrengthFieldStrength
15 dB15 dBII
10 dB10 dBII
5 dB 5 dB II
ImaxImax
analogueanalogue
Resistance to interference• Digital reception
TTERRESTRIAL
Introduction DRM DAB DVB Conclusion
Dr. A. Kholod (FM/GF) 19
Higher picture resolution
SDTVSDTV EDTV or HDTVEDTV or HDTV
4:3 Aspect Ratio4:3 Aspect Ratio 16:9 Aspect Ratio16:9 Aspect Ratio
TTERRESTRIAL
Introduction DRM DAB DVB Conclusion
• Requires higher bit rate
Dr. A. Kholod (FM/GF) 20
18.4 Mbit/s18.4 Mbit/s
Multicasting
Program 1Program 1
Program 2Program 2
Program 3Program 3
Program 4Program 4
Data (MHP)Data (MHP)
TTERRESTRIAL
Introduction DRM DAB DVB Conclusion
Dr. A. Kholod (FM/GF) 21
PortableStationary
Mobile
Guard interval Modulation Code rate 1/4 1/8 1/16 1/32
1/2 5.0 5.5 5.9 6.0 2/3 6.6 7.4 7.8 8.0 3/4 7.5 8.3 8.8 9.1 5/6 8.3 9.2 9.8 10.1
QPSK
7/8 8.7 9.7 10.3 10.6 1/2 10.0 11.1 11.7 12.1 2/3 13.3 14.8 15.6 16.1 3/4 14.9 16.6 17.6 18.1 5/6 16.6 18.4 19.5 20.1
16 – QAM
7/8 17.4 19.4 20.5 21.1 1/2 14.9 16.6 17.6 18.1 2/3 19.9 22.1 23.4 24.1 3/4 22.4 24.9 26.4 27.1 5/6 24.9 27.7 29.4 30.2
64 – QAM
7/8 26.1 29.0 30.7 31.7
Variety of operation modes TTERRESTRIAL
Introduction DRM DAB DVB Conclusion
• Different net bit rates
Dr. A. Kholod (FM/GF) 22
• Deutsch-schweiz– SF1– SF2– TSR1– TSI 1
• Suisse Romande– TSR1– TSR2– SF1– SF2
DVB-T programs
• SvizzeraItaliana– TSI1– TSI2– SF1– TSR1
TTERRESTRIAL
Introduction DRM DAB DVB Conclusion
Dr. A. Kholod (FM/GF) 23
Summary
Introduction DRM DAB DVB Conclusion
TTERRESTRIAL
• Broadcasting future is digital because of (but not only):- spectrum efficiency- cost reduction- enhanced quality- service added value
• DVB-T is a hot topic in Europe now
Dr. A. Kholod (FM/GF) 24
Thank you for your attention
to be continued …