BroadcastSyst.ppt

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


• 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)



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+

=


“0”“0”

“1”“1”

“?”“?”


System failure characteristic

edge of service

area

edge of service

area

DistanceDistance FarFarNearNear

Qu

alit

yQ

ual

ity

PoorPoor

ExcellentExcellent

AnalogueAnalogue

DigitalDigital



• Radio

Digital broadcasting technologies

• Television

- FM: UKW

- AM: LW / MW / SW



• 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



DRM vs analogue quality


• AM

• DRM

Listen

Listen


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



• 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




• 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



• Portable indoor reception

20002005

2000: 60 %2005: 70 %2008: 80 %

national coverage

2006

2007

2008

2009

DAB in Switzerland


• 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




Television Transmission Paths

TTERRESTRIAL

terrestrialterrestrial

satellitesatellite

SSATELLITE

cablecableC

CABLE

In progress

Ok

Ok


• 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



Different reception modes

fixedoutdoorfixedoutdoor portable

indoorportable

indoor

mobilemobile

TTERRESTRIAL



Resistance to interference

CC

II

50 dB50 dB40 dB40 dB35 dB35 dB30 dB30 dB25 dB25 dB20 dB20 dB

IIIIIIIIII

FieldStrengthFieldStrength

• Analogue receptionT

TERRESTRIAL



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



Higher picture resolution

SDTVSDTV EDTV or HDTVEDTV or HDTV

4:3 Aspect Ratio4:3 Aspect Ratio 16:9 Aspect Ratio16:9 Aspect Ratio

TTERRESTRIAL


• Requires higher bit rate


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



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


• Different net bit rates


• Deutsch-schweiz– SF1– SF2– TSR1– TSI 1

• Suisse Romande– TSR1– TSR2– SF1– SF2

DVB-T programs

• SvizzeraItaliana– TSI1– TSI2– SF1– TSR1

TTERRESTRIAL



Summary


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


Thank you for your attention

to be continued …

BroadcastSyst.ppt

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