1 australian dttb lab tests, methodology & results summary presentation by: neil pickford...

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AustralianDTTB Lab Tests, Methodology & Results Summary

AustralianDTTB Lab Tests, Methodology & Results Summary

Presentation by: Neil PickfordPresentation by: Neil Pickford

Communications LaboratoryCommunications Laboratory

http://www.commslab.gov.au/http://www.commslab.gov.au/

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OverviewOverview Digital Television Objectives & TechnologyDigital Television Objectives & Technology DTTB Transmission TechnologyDTTB Transmission Technology The Australian Test ProgramThe Australian Test Program Laboratory Tests - Test RigLaboratory Tests - Test Rig Laboratory Tests - Main ResultsLaboratory Tests - Main Results Field Test Objectives & EquipmentField Test Objectives & Equipment Summary Field Test ResultsSummary Field Test Results Selection Process & CriteriaSelection Process & Criteria Selection Result & FutureSelection Result & Future

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Digital TelevisionDigital Television

Why digital?Why digital?To Overcome LimitationsTo Overcome Limitations

of Analog Televisionof Analog Television Noise free picturesNoise free pictures Higher resolution imagesHigher resolution images

Widescreen / HDTVWidescreen / HDTV No GhostingNo Ghosting Multi-channel, Enhanced Multi-channel, Enhanced

Sound ServicesSound Services Other Data services.Other Data services.

4

World TV StandardsWorld TV Standards

Australia like China & Malaysia are PALAustralia like China & Malaysia are PAL

NTSCNTSCPALPALSECAMSECAMPAL/SECAMPAL/SECAM

UnknownUnknown

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Transmission Bandwidth - VHFTransmission Bandwidth - VHF

Australia & Malaysia are 7 MHz, Australia & Malaysia are 7 MHz, China is 8 MHzChina is 8 MHz

6 MHz6 MHz7 MHz7 MHz8 MHz8 MHzNot in UseNot in Use

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Transmission Bandwidth - UHFTransmission Bandwidth - UHF

6 MHz6 MHz7 MHz7 MHz8 MHz8 MHzNot in UseNot in Use

Australia is Alone using 7 MHz on UHFAustralia is Alone using 7 MHz on UHF

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Australian Population DistributionAustralian Population Distribution

Uneven Populationdistribution

Wide areas where few people live

Noise LimitedTransmissionenvironment

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Free To Air Television (FTA)Free To Air Television (FTA)

5 Networks - 3 Commercial, 2 Government5 Networks - 3 Commercial, 2 Government

Important part of Australian entertainmentImportant part of Australian entertainment

Majority of Australian audience is watchingMajority of Australian audience is watching

No television receiving licencesNo television receiving licences

National broadcasters funded from taxationNational broadcasters funded from taxation

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Pay TV - Cable, MDS & SatellitePay TV - Cable, MDS & Satellite

Only a small business in AustraliaOnly a small business in Australia Less then 400,000 subscribersLess then 400,000 subscribers Less than 7% of householdsLess than 7% of households

Indoor receptionIndoor receptionAround 30% of Australians watch FTA using Around 30% of Australians watch FTA using indoor antennasindoor antennas

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Program Quality Vs QuantityProgram Quality Vs Quantity

Australians have a low number of Australians have a low number of

available television channelsavailable television channels

Television program budget is spread between Television program budget is spread between

fewer programsfewer programs

Australians used to watching high quality Australians used to watching high quality

programming at high technical quality.programming at high technical quality.

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All decoders sold in Australia will All decoders sold in Australia will be MP@HL capable allowing all be MP@HL capable allowing all viewers access to HD resolution viewers access to HD resolution

when it becomes availablewhen it becomes available

MP@MLMP@ML MP@HLMP@HL

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Enabling TechnologiesEnabling Technologies

Source digitisation (Rec 601 digital studio)Source digitisation (Rec 601 digital studio) Compression technology (MPEG, AC-3)Compression technology (MPEG, AC-3) Data multiplexing (MPEG)Data multiplexing (MPEG) Display technology (large wide screens)Display technology (large wide screens)

Transmission technology Transmission technology (modulation)(modulation)

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Transmission TechnologyTransmission Technology

The transmission system is used to transport the The transmission system is used to transport the information to the consumer.information to the consumer.

The system protects the information being The system protects the information being carried from the transmission environmentcarried from the transmission environment

Current Australian analog television uses the Current Australian analog television uses the PAL-B AM modulation systemPAL-B AM modulation system

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Digital TV Transmission Technology

Digital TV Transmission Technology

The transmission The transmission system is asystem is a “data pipe” “data pipe”

Transports data rates Transports data rates of around 20 Mb/sof around 20 Mb/s

Transports data in Transports data in individual containers individual containers called packetscalled packets

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Digital TV Transmission SystemsDigital TV Transmission Systems

Australia has been following Digital TV & HDTVAustralia has been following Digital TV & HDTV Europeans Europeans - Digital SDTV - Digital SDTV

- 8 MHz on UHF- 8 MHz on UHF- DVB-T (COFDM)- DVB-T (COFDM)

AmericansAmericans - Digital HDTV - Digital HDTV - 6 MHz VHF/UHF- 6 MHz VHF/UHF- ATSC (8-VSB)- ATSC (8-VSB)

Japanese Japanese - Integrated Broadcasting- Integrated Broadcasting- ISDB (BST-OFDM)- ISDB (BST-OFDM)

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8-VSB - USA8-VSB - USA

Developed by the advance television systems Developed by the advance television systems committee - ATSCcommittee - ATSC

Developed for use in a 6 MHz channelDeveloped for use in a 6 MHz channel A 7 MHz variant is possible.A 7 MHz variant is possible.

Uses a single carrier with pilot toneUses a single carrier with pilot tone 8 level amplitude modulation system8 level amplitude modulation system Single Payload data rate of 19.39 Mb/sSingle Payload data rate of 19.39 Mb/s Relies on adaptive equalisationRelies on adaptive equalisation Existing AM technology highly developedExisting AM technology highly developed

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COFDM - EuropeCOFDM - Europe Developed by the digital video Developed by the digital video

broadcasting project group - DVBbroadcasting project group - DVB Uses similar technology to DRBUses similar technology to DRB Uses 1705 or 6817 carriersUses 1705 or 6817 carriers Variable carrier modulation types are defined allowing Variable carrier modulation types are defined allowing

Payload data rates of 5-27 Mb/s in 7 MHzPayload data rates of 5-27 Mb/s in 7 MHz Developed for 8 MHz channelsDeveloped for 8 MHz channels

A 7 MHz variant has been produced and testedA 7 MHz variant has been produced and tested

Can use single frequency networks - SFNsCan use single frequency networks - SFNs New technology with scope for continued improvement & New technology with scope for continued improvement &

developmentdevelopment

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The Australian DTTB Test ProgramThe Australian DTTB Test Program

Australia is interested in a Digital HDTV FutureAustralia is interested in a Digital HDTV Future Australia has a Unique Broadcasting Australia has a Unique Broadcasting

EnvironmentEnvironment Overseas Digital TV Developments were Overseas Digital TV Developments were

interesting but the results could not be directly interesting but the results could not be directly related to Australia.related to Australia.

To make informed decisions we needed to To make informed decisions we needed to collect information relevant to our situation.collect information relevant to our situation.

We had a few Questions.We had a few Questions.

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Aims of Australian DTTB Testing-1Aims of Australian DTTB Testing-1

Australia needed to know:Australia needed to know: How does DTTB perform with VHF PAL-B?How does DTTB perform with VHF PAL-B? What Protection does PAL require from the What Protection does PAL require from the

DTTB service for:DTTB service for: Co-Channel?Co-Channel? Adjacent Channel?Adjacent Channel? Subjective Assessment Subjective Assessment Is Signal level a factor?Is Signal level a factor?

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Aims of Australian DTTB Testing-2Aims of Australian DTTB Testing-2 How Quickly does the system degrade?How Quickly does the system degrade? What are the real system thresholds?What are the real system thresholds?

Signal LevelSignal Level Carrier to NoiseCarrier to Noise Payload Data Rate in 7 MHzPayload Data Rate in 7 MHz

How does DTTB cope with Interference?How does DTTB cope with Interference? What is a typical Noise Figure for a DTTB RxWhat is a typical Noise Figure for a DTTB Rx

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Aims of Australian DTTB Testing-3Aims of Australian DTTB Testing-3 What Protection does DTTB require from the What Protection does DTTB require from the

PAL-B service for:PAL-B service for: Co-Channel?Co-Channel? Adjacent Channel?Adjacent Channel? Is Signal level a factor?Is Signal level a factor?

What Protection does DTTB require from other What Protection does DTTB require from other DTTB services?DTTB services?

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Aims of Australian DTTB Testing-4Aims of Australian DTTB Testing-4 How does DTTB perform in a 7 MHz How does DTTB perform in a 7 MHz

Channel Environment?Channel Environment? How sensitive is DTTB to practical How sensitive is DTTB to practical

Transmission Equipment?Transmission Equipment?How important is:How important is: Transmitter Linearity?Transmitter Linearity? Transmitter Precorrection?Transmitter Precorrection? Transmitter Output Filtering?Transmitter Output Filtering? Combined Feeder/Antenna Systems?Combined Feeder/Antenna Systems?

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Aims of Australian DTTB Testing-5Aims of Australian DTTB Testing-5 Is DTTB affected by Multipath Echoes?Is DTTB affected by Multipath Echoes?

Are Pre-Echoes a Problem?Are Pre-Echoes a Problem? What happens past the Guard interval?What happens past the Guard interval?

Is DTTB affected by Doppler Shift?Is DTTB affected by Doppler Shift? Is DTTB affected by Dynamic Flutter?Is DTTB affected by Dynamic Flutter? Is DTTB affected by Impulsive Interference?Is DTTB affected by Impulsive Interference? How does DTTB perform in the Field cw PALHow does DTTB perform in the Field cw PAL

Lots of Questions butLots of Questions butFew Definitive Answers!Few Definitive Answers!

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Scope of TestsScope of Tests

The test program began with the aim of The test program began with the aim of answering these questions for DVB-Tanswering these questions for DVB-T

During the early stages of testing ATSC was During the early stages of testing ATSC was floated as a Candidate Digital TV Systemfloated as a Candidate Digital TV System

The test program’s scope was increased and a The test program’s scope was increased and a comparative focus adopted.comparative focus adopted.

All tests were designed to be as generally All tests were designed to be as generally applicable as possible to any Digital TV applicable as possible to any Digital TV Modulation System.Modulation System.

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Order of MeasurementsOrder of Measurements

FACTS Advanced TV Specialists Group FACTS Advanced TV Specialists Group directed the priority of Testingdirected the priority of Testing

Laboratory Tests FirstLaboratory Tests First DTTB into PAL protection DTTB into PAL protection DTTB System ParametersDTTB System Parameters PAL into DTTB protectionPAL into DTTB protection Other Interferers & DegradationsOther Interferers & Degradations

Field Tests LaterField Tests Later

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900 m

Off Air 7 & 9 Test

CoaxDoppler

RS 422Taxi

TxLO

HPIB

PAL RF

Rig LO

SpectrumAnalyser

HPIB

HPIB To/ From Other Yellow Shaded Equipment

10 MHz

10 MHz GPSReference

10 MHzReference

10 MHz L-BandGPS

LinkEcho/ Doppler

DTTB IF36.65 MHz

IF

+7 dBm

Coax Echo200 m

300 m

CoaxEcho/ Doppler

RS2329600Baud

Pal

HPIB CoaxComms Link

Ethernet

PAL/ CW

Ch 8DTTB

EchoLO

35.3 MHzCofdm IF

Test

O/ P

Power

10baseTEthernet

PAL IF

PAL LO CW/ SCM

RS23219.2 Kb/ s

HPIB

TTL Clock& data

Combined DTTB Signal RG-6 Cable Loss 3.85 dB

PAL/ CW+DTTB

SDI

RS422Taxi

Ch8Cofdm

PAL PAL

ZHL-1A Amp

Plisch SBUF PAL Stereo IF

Modulator

Sony DVW-A500PDigital Betacam

Tektronix TSG-271PAL Test Generator

DMV 2kCOFDMModulator

DMV Multiplexer

DMV MPEG Coder

DMV MPEG Coder

Switch

RGB Monitor

Anritsu ME520BBit Error Rate Meter

DTTB Receiver

Linux PC

HP37204HPIB Extender

HP3708Carrier to Noise

Test Set

DMVMCC

HP-436APower Meter

TransmitterUnderTest

HP8447EAmp

AR2098Amp HP-436A

Power Meter

Pal TV Under Test

Rx Control PC

HP37204HPIB Extender

Off air PAL Video

VT-100

500W30dBAttenuator

HP 70000Spectrum Analyser

HP8447CAmp

HP8447CAmp

RG-213 Coaxial Delay On Laboratory Roof

-10 dB Min

235.150 MHz-13 dBmPAL LO

191.500 MHz-20.1 dBmSCM/ CW

+21.7 dB +10.2 dB

-22.8 dB

Ch 7-9BW 13MHz

226.800 MHz+0 dBmDTTB LO

Ch 7-9BW 13MHz +17.9 dB

50 Ohm

DTTBSignalLevelDTTB Cal

Level Adjust

-10 dB

PAL/ CWSignalLevel

0 dB

Tx FilterVHF Ch 8BW 7MHz

VHF Ch 8191.500 MHzBW 7MHz

DirectSignal

DirectCalibrate

EchoSignal

HP8663ACOFDM 226.800 MHz8-VSB 235.500 MHz

NEC +6.2 dBmHarris +7.0 dBm

DTTB Tx LO

ManualTx Drive

Rig/ TxSelect

+29.3 dB

228..150 MHz+7 dBmEcho LO

-27.6 dBm

0 dB Cal Level for DTTB Rx -23.75 dBm0 dB Cal Level for Pal TV Rx -27.6 dBm

-27.6 dBm

DUTPort

MeasurePort

AR10W1000Amp

HP8447EAmp

-16 dB

UHF Ch 44641.5 MHz +22 dB +40 dB

450 MHz+7 dBm

Mix Up LO

191.5 MHzBW 7 MHz

PU11VPUHF TxPanel

8 MHz IF FilterIF amp

Plisch TV Receiver

Doppler LO 228.150 MHz Ch 44 LO 678.150 MHz

+7 dBm

HP Amp

UHF Ch 44641.5 MHz

3 Element VHFCh 8 Beam

Hills Ch 8-11TV antenna

2 km VHF Link

2 kmUHFLink

96 ElementUHF Antenna

HP9836Controller

Yellow Shaded Items are under Control of HP9836 via HPIB

Direct/ EchoCombiner

D/ UCombinerZSC-2-4

Tx DriveLevel

GPSFrequency Reference10 MHz

L-BandGPS

GPSFrequency Reference10 MHz

TestSplitterZSC-2-4

Unwanted Signal Path

Desired Signal Path

All the Equipment Within thisDashed Box is inside Shielded room

with the DTTB Modulator

All Equipment within DashedBox is in Separate ShieldedRoom with DTTB Receiver

Translator Link EquipmentAt University of Canberra

Link UHF Receive Equipment Near Roof Access

Transmission EquipmentLocated in Main Laboratory

HP8447CAmp

Dash-Dot Line IndicatesModulation Equipment

Under Test

+30 dB

+30 dB

-20 dB

-13.4 dBm

-16.5dBm

HP5383AFrequency

Meter

ZSC-2-4

MUF2-Z2 Tv Ant

ZFM-11 ZFM-11

GPS Ant

GPS Ant

ZFM-11

MAV-11Amp

MAV-11Amp

HP8447CAmp

+27 dB

-23.8 dBm

+5.4 dBm

-21.4dBm -32.6

dBm

-14.7dBm

-15.3dBm

-15.9dBm

-16.5 dBm

-16.4 dBm

+6.8 dBm

+8.0 dBm-2.4dBm

-23.8 dBm

75 W Input

-30 dBm

-18 dBm

0 dBm

+11 dBm

-24.5 dBm

3 W Input

~3 W

-48.6 dBm

-50dBm

-38 dBm

+12 dB

-50dBm

-23 dBm -27 dBm -42.8dBm

-19dBm

+24 dBm

+7 dBm

-69 dBm-57 dBm-60 dBm

-35 dBm

-41dBm

IF=36.15 MHz

-8 dBm

-20 dBm

-10 dBm-17 dBm

-18 dBm

0 dB

-19 dBm

-22 dBm

-19dBm

0 dB-14 dBm-0.8 dBm 2.1 dB

20.4 dB Link 7.0 dB Coax

+48.55 dBm

+18.55 dBm

-18.5dBm

-17dBm

-23.8 dBm

-23.8 dBm

-23 dBm

Power Levels for two Test Modes Shown3 W +33 dBm for Link Echo Tests75 W +48.6 dBm for Coax Echo Tests

ZFSC-2-4

Test Rig - Block DiagramTest Rig - Block Diagram

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Laboratory Tests - Test RigLaboratory Tests - Test RigEUTEUTC/N Set & AttenuatorsC/N Set & Attenuators PAL & CWPAL & CW

Spectrum AnalysersSpectrum AnalysersControlControlComputerComputer

DomesticDomesticTelevisionTelevisionReceiverReceiver

ModulatorModulatorControlControl

ComputersComputers

Plot &Plot &PrintingPrinting

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Test Rig - Modulation EquipmentTest Rig - Modulation Equipment

COFDMCOFDMModulatorModulator

MPEG MuxMPEG Mux

MPEG EncoderMPEG Encoder

MPEG EncoderMPEG Encoder

MPEG MuxMPEG Mux

8-VSB8-VSBModulatorModulator

RF LORF LO

Power MeterPower Meter PAL & CWPAL & CWInterferenceInterferenceGeneratorsGenerators

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Laboratory Tests - TransmittersLaboratory Tests - Transmitters

Tx LOTx LOSpectrumSpectrumAnalyserAnalyser

Digital CRODigital CRO

HarrisHarrisExciterExciter

Power MeterPower MeterHarrisHarris1 kW 1 kW TxTx

NEC 200 W TxNEC 200 W Tx

LoadsLoads

Echo CombinerEcho Combiner

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Digital Transmitters TCN-9 SydneyDigital Transmitters TCN-9 Sydney

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Lab Tests - VHF/UHF TransposerLab Tests - VHF/UHF Transposer

VHF Input FilterVHF Input FilterRF AmpRF Amp

MixerMixer

10 Watt UHF10 Watt UHFAmplifierAmplifier

RF LORF LO

Power SupplyPower Supply

Level AdjustLevel Adjust

UHF AmpsUHF Amps

UHF BPF FilterUHF BPF Filter

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COFDM - Commercial ReceiverCOFDM - Commercial Receiver News Data Systems - System 3000News Data Systems - System 3000

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COFDM - Test Rx HardwareCOFDM - Test Rx Hardware

34

8-VSB - Test Rx Hardware8-VSB - Test Rx Hardware

8-VSB - Test Receiver Hardware8-VSB - Test Receiver Hardware

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Main Results - Lab TestsMain Results - Lab Tests C/N ATSC 4 dB better than DVB-T.C/N ATSC 4 dB better than DVB-T.

This Advantage offset by Poor Noise FigureThis Advantage offset by Poor Noise Figure DVB-T is better than ATSC for MultipathDVB-T is better than ATSC for Multipath ATSC is better than DVB-T for Impulse NoiseATSC is better than DVB-T for Impulse Noise ATSC cannot handle Flutter or Doppler EchoesATSC cannot handle Flutter or Doppler Echoes ATSC is very sensitive to Transmission system ATSC is very sensitive to Transmission system

impairments and IF translationimpairments and IF translation DVB-T is better at handling Co-channel PALDVB-T is better at handling Co-channel PAL DVB-T is better rejecting on channel interference DVB-T is better rejecting on channel interference

(CW)(CW)

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8-VSB & COFDM - Spectrum8-VSB & COFDM - Spectrum

8-VSBCOFDM

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Digital Modulation - 8-AMDigital Modulation - 8-AM

3 Bits/Symbol3 Bits/Symbol

+7+7

-5-5

-3-3

-1-1

+1+1

+3+3

+5+5

-7-7

8-VSB - Coaxial Direct Feed through Tuner on Channel 8 VHF8-VSB - Coaxial Direct Feed through Tuner on Channel 8 VHFBefore EqualiserBefore Equaliser After EqualiserAfter Equaliser

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Spectrum of COFDM DTTBSpectrum of COFDM DTTB

6.67 MHz in 7 MHz Channel6.67 MHz in 7 MHz Channel

AlmostAlmostRectangularRectangular

ShapeShape

1705 or 6817 Carriers1705 or 6817 Carriers

7 MHz Carrier Spacing7 MHz Carrier Spacing2k Mode 3.91 kHz2k Mode 3.91 kHz8k Mode 0.98 kHz8k Mode 0.98 kHz

7.61 MHz in 8 MHz Channel7.61 MHz in 8 MHz Channel

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7 MHz Theoretical DVB Transmission signal spectrum

-60

-50

-40

-30

-20

-10

0

-8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8

7 MHz COFDM Modulator Spectrum7 MHz COFDM Modulator Spectrum

2k 1/32 Guard2k 1/32 Guard

00

-10-10

-20-20

-30-30

-40-40

-50-50

00-1-1-2-2-3-3-4-4-5-5-6-6-7-7-8-8 11 22 33 44 55 66 77 88Frequency Offset (MHz)Frequency Offset (MHz)

Pow

er S

pect

rum

Den

sity

(dB

)P

ower

Spe

ctru

m D

ensi

ty (

dB)

42

64-QAM - Perfect & Failure64-QAM - Perfect & Failure

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Channel Estimation & EqualisationChannel Estimation & Equalisation

TimeTime

TimeTime

ATSCATSC

DVB-TDVB-T

Data Data Continuous PilotContinuous Pilot

Occasional PilotOccasional PilotSpecial DataSpecial Data

Frequency SpectrumFrequency Spectrum

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General Parameters - Aust TestsGeneral Parameters - Aust Tests

ParameterParameter DVB-TDVB-T ATSCATSC

Data PayloadData Payload 19.35 Mb/s19.35 Mb/s 19.39 Mb/s19.39 Mb/s

CarriersCarriers 17051705 11

Symbol TimeSymbol Time 256 us256 us 93 ns93 ns

Time InterleavingTime Interleaving 1 Symbol1 Symbol 4 ms4 ms

Reed Solomon code rateReed Solomon code rate 188/204188/204 187/207187/207

IF Bandwidth (3 dB)IF Bandwidth (3 dB) 6.67 MHz6.67 MHz 5.38 MHz5.38 MHz

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General ParametersGeneral Parameters


IF centre FrequencyIF centre Frequency 35.3 MHz35.3 MHz 44.0 44.0 MHzMHz

Receiver AFC rangeReceiver AFC range 11.5 kHz11.5 kHz 359 kHz359 kHz

Latency including MPEG Latency including MPEG coding SDTV 8 Mb/scoding SDTV 8 Mb/s 37 Frames37 Frames

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Payload Bitrate Mb/s Pal C/I ProtectionCOFDM

MOD TYPE

FEC Code Rate

Sys C/N (dB)

Min Sig Level

(dBuV)

Calc Rx NF (dB)

Guard 1/4

(Mb/s)

Guard 1/8

(Mb/s)

Guard 1/16

(Mb/s)

Guard 1/32

(Mb/s)QPSK 1/2 5.4 11.7 4.8 4.35 4.84 5.12 5.28QPSK 2/3 6.6 13.2 5.1 5.81 6.45 6.83 7.04QPSK 3/4 7.6 14.8 5.7 6.53 7.26 7.68 7.92QPSK 5/6 8.7 16.8 6.6 7.26 8.06 8.54 8.80QPSK 7/8 9.5 19.2 8.2 7.62 8.47 8.96 9.24

16-QAM 1/2 11.2 17.7 5.0 8.71 9.68 10.25 10.5616-QAM 2/3 13.0 19.6 5.1 11.61 12.90 13.66 14.0716-QAM 3/4 14.1 20.9 5.3 13.06 14.51 15.37 15.8316-QAM 5/6 15.5 22.9 5.9 14.51 16.13 17.08 17.5916-QAM 7/8 16.3 24.9 7.1 15.24 16.93 17.93 18.4764-QAM 1/2 16.8 23.3 5.0 13.06 14.51 15.37 15.8364-QAM 2/3 19.1 25.2 4.6 17.42 19.35 20.49 21.1164-QAM 3/4 20.6 27.5 5.4 19.59 21.77 23.05 23.7564-QAM 5/6 22.2 30.0 6.3 21.77 24.19 25.61 26.3964-QAM 7/8 23.7 32.4 7.2 22.86 25.40 26.89 27.718-VSB 2/3 15.1 27.2 11.2 - - - 19.39

Blue Payload Figures are 188/204 scaled from actual measurementRed Figures are calculated from the 1/32 Guard interval data

C/N, NF & Payload Rate TableC/N, NF & Payload Rate Table

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AWGN Receiver PerformanceAWGN Receiver Performance


Carrier to Noise Threshold Carrier to Noise Threshold (in native system BW)(in native system BW) 19.1 dB19.1 dB 15.1 dB15.1 dB

Simulated Theoretical C/N Simulated Theoretical C/N for optimum systemfor optimum system 16.5 dB16.5 dB 14.9 dB14.9 dB

Minimum Signal LevelMinimum Signal Level 25.2 dBuV25.2 dBuV 27.2 dBuV27.2 dBuV

Receiver noise figureReceiver noise figure 4.6 dB4.6 dB 11.2 dB11.2 dB

Rx Level for 1 dB C/N LossRx Level for 1 dB C/N Loss 34 dBuV34 dBuV 35 dBuV35 dBuV

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Receiver ParametersReceiver Parameters

Guard interval Guard interval

Affects payload data rate and echo performance Affects payload data rate and echo performance No impact on general receiver parameters such as No impact on general receiver parameters such as

C/N & Signal level.C/N & Signal level. COFDM Transmission Parameter Signalling COFDM Transmission Parameter Signalling

(TPS) - receiver automatically determines (TPS) - receiver automatically determines the modulation type, FEC & Guard Intervalthe modulation type, FEC & Guard Interval

49

DTTB System Multipath CharacterDTTB System Multipath Character

00 33 1515 2525

15151919

3535

Multipath Level ( - dB)Multipath Level ( - dB)

(64QAM, 2/3, 1/8)(64QAM, 2/3, 1/8)

C/N

Th

resh

old

(d

B)

C/N

Th

resh

old

(d

B)

Indoor Antenna Outdoor Antenna

(Conditions: Static multipath, Equal Rx NF, (Conditions: Static multipath, Equal Rx NF, No Co-channel or impulse interference)No Co-channel or impulse interference)

COFDMCOFDM

8VSB8VSB

51

AWGN PerformanceAWGN Performance C/N 4 dB more power required for DVB-T to C/N 4 dB more power required for DVB-T to

achieve the same coverage as ATSC.achieve the same coverage as ATSC.

Better C/N performance ATSC offset by poor Better C/N performance ATSC offset by poor receiver noise figure receiver noise figure

ATSC C/N is very close to the theoretical DVB-T ATSC C/N is very close to the theoretical DVB-T implementation is still over 2.5 dB higher than implementation is still over 2.5 dB higher than the simulated margin.the simulated margin.

Other DVB-T modes have different C/N Other DVB-T modes have different C/N Thresholds and Data RatesThresholds and Data Rates

52

Multipath & Flutter MeasurementsMultipath & Flutter MeasurementsParameterParameter DVB-TDVB-T ATSCATSC

7.2 us Coax pre ghost7.2 us Coax pre ghost 0 dB0 dB -13.5 dB-13.5 dB

7.2 us Coax post ghost7.2 us Coax post ghost 0 dB0 dB -2.2 dB-2.2 dB

Echo correction rangeEcho correction range 32 us32 us +3 to -20 +3 to -20 usus

Doppler single echo performance Doppler single echo performance (-3 dB echoes)(-3 dB echoes) 140 Hz140 Hz 1 Hz1 Hz

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Doppler Echo - 7.5 us CoaxDoppler Echo - 7.5 us CoaxDTTB 7.5 us Single Coax Doppler Echo

-25

-20

-15

-10

-5

0

-500 -400 -300 -200 -100 0 100 200 300 400 500

COFDM Post Echo

8-VSB Post Echo

Ech

o L

evel

E/D

(dB

)

Frequency Offset (Hz)0-500 200-200 500

-20

-10

-5

0

-15

-25

COFDM8-VSB

54

Multipath & Flutter - OverviewMultipath & Flutter - Overview

ATSC system 2 Equaliser modes ATSC system 2 Equaliser modes

Rx Eq switches to fast mode when short variable Rx Eq switches to fast mode when short variable echoes are detected. echoes are detected.

Lab Tests - slow equalisation mode. Lab Tests - slow equalisation mode. 8 VSB degrades more rapidly when multipath 8 VSB degrades more rapidly when multipath

echo exceeds -7 dBecho exceeds -7 dB

COFDM works up to 0 dB in a white noise COFDM works up to 0 dB in a white noise environment but in this condition is very environment but in this condition is very fragile. fragile.

55

Transmitter Performance SensitivityTransmitter Performance Sensitivity


Transmitter/Translator LinearityTransmitter/Translator Linearity & Inter-mod Sensitivity & Inter-mod Sensitivity LowLow HighHigh

Group Delay / Combiner / Group Delay / Combiner / Filter SensitivityFilter Sensitivity LowLow < 50 ns< 50 ns

56

Transmission Strategies - 1Transmission Strategies - 1

Suggested Transmission System Suggested Transmission System performance maintenance strategyperformance maintenance strategy

DVB-T - DVB-T - Manual Maintenance andManual Maintenance andstatic pre-correction - same as PALstatic pre-correction - same as PAL

ATSC - ATSC - Automatic Dynamic pre-correctorAutomatic Dynamic pre-correctorMeasures performance and makesMeasures performance and makespre-correction adjustments on-linepre-correction adjustments on-line

57

Transmission Strategies - 2Transmission Strategies - 2

Gap Fill coverage - System StrategyGap Fill coverage - System Strategy DVB-T - DVB-T -

IF Translator IF Translator Non Regenerative On Channel Repeater (OCR)Non Regenerative On Channel Repeater (OCR) Digital RepeaterDigital Repeater Single Frequency NetworkSingle Frequency Network

ATSC - ATSC - Digital RepeaterDigital Repeater Non Regenerative OCR (Low Signal Environs)Non Regenerative OCR (Low Signal Environs)

58

Transmission Performance - 1Transmission Performance - 1

ATSC very sensitive to transmission ATSC very sensitive to transmission impairments as it uses up correction impairments as it uses up correction capacity in the receiver equaliser.capacity in the receiver equaliser.

ATSC equaliser has to correct the response ATSC equaliser has to correct the response characteristic of the whole channel.characteristic of the whole channel.

DVB-T equaliser uses pilot carriers spread DVB-T equaliser uses pilot carriers spread throughout the spectrum to equalise the throughout the spectrum to equalise the channel in small 16-50 kHz sections. channel in small 16-50 kHz sections.

59

Transmission Performance - 2Transmission Performance - 2

ATSC Dynamic Pre-corrector will be difficult ATSC Dynamic Pre-corrector will be difficult to apply in the combined antenna systems to apply in the combined antenna systems used in Australiaused in Australia

Zenith suggest transmission without using a Zenith suggest transmission without using a transmitter output filter to avoid group delay transmitter output filter to avoid group delay problems with 8-VSB. problems with 8-VSB.

ATSC 6 MHz system operating in a 7 MHz ATSC 6 MHz system operating in a 7 MHz channel helps this situation.channel helps this situation.

61

Impulse Noise - ResultsImpulse Noise - Results

Impulse SensitivityImpulse Sensitivity (Differential to PAL grade 4) (Differential to PAL grade 4)

DVB-TDVB-T 9 -14 dB 9 -14 dB ATSC ATSC 17-25 dB17-25 dB

Difficult to measure & characterise.Difficult to measure & characterise.

Mainly affects the lower VHF frequenciesMainly affects the lower VHF frequencies

ATSC is 8 to 11 dB better at handling ATSC is 8 to 11 dB better at handling impulsive noise than DVB-Timpulsive noise than DVB-T

62

Impulse Noise - PlotImpulse Noise - Plot

COFDM8-VSB

63

Impulse Noise - OverviewImpulse Noise - Overview ATSC only has a few data symbols affected ATSC only has a few data symbols affected

by any normal impulsive phenomenonby any normal impulsive phenomenon

The DVB-T COFDM demodulation (FFT) The DVB-T COFDM demodulation (FFT) spreads the energy from a broad spectrum spreads the energy from a broad spectrum impulse across all carriers leading to impulse across all carriers leading to massive data loss when the impulse is massive data loss when the impulse is large enough. large enough.

64

DTTB into PAL - SubjectiveDTTB into PAL - SubjectiveD T T B in to P A L B P ro t e c t io n D /U (d B )

S y s t e m T e s t D e s c rip t io n M e a n S td D e v N u m M in M e d ia n M a xD VB -T 7 M H z C h 7 lo w e r a d j. c h . -9.5 3.3 12 -14.0 -10.0 -4.0T ro p o s p h e ric C h 8 C o -C h a n n e l 35.8 1.4 12 33.5 36.0 38.5In t e rfe re n c e C h 9 u p p e r a d j. c h . -10.6 4.9 12 -20.0 -10.0 -3.0

D VB -T 7 M H z C h 7 lo w e r a d j. c h . -5.3 3.8 12 -9.5 -6.5 2.5C o n t in u o u s C h 8 C o -C h a n n e l 41.1 2.0 12 38.5 40.8 45.0In t e rfe re n c e C h 9 u p p e r a d j. c h . -6.4 4.3 12 -14.0 -6.8 1.0

D VB -T 7 M H z C h 7 lo w e r a d j. c h . 3.5 3.8 12 -2.5 2.8 10.0Limit o f C h 8 C o -C h a n n e l 50.4 0.9 14 48.5 50.3 52.0

P e rc e p t ib ilit y C h 9 u p p e r a d j. c h . 5.1 5.8 16 -1.0 3.8 20.0A T S C 6 M H z C h 7 lo w e r a d j. c h . -7.0 3.4 15 -12.5 -7.0 -2.0T ro p o s p h e ric C h 8 C o -C h a n n e l 38.7 2.6 41 34.5 38.5 44.0In t e rfe re n c e C h 9 u p p e r a d j. c h . -7.1 3.5 17 -14.0 -6.0 -3.5

A T S C 6 M H z C h 7 lo w e r a d j. c h . -0.9 4.3 15 -5.5 -2.0 8.0C o n t in u o u s C h 8 C o -C h a n n e l 45.5 2.2 41 41.0 45.0 50.5In t e rfe re n c e C h 9 u p p e r a d j. c h . -0.3 2.9 17 -5.5 0.0 3.0

A T S C 6 M H z C h 7 lo w e r a d j. c h . 5.0 4.4 15 0.0 4.0 13.0Limit o f C h 8 C o -C h a n n e l 51.4 2.5 41 47.0 51.5 56.5

P e rc e p t ib ilit y C h 9 u p p e r a d j. c h . 5.4 3.1 17 0.0 4.5 10.5

GradeGrade

33

33

44

44

65

DTTB into PAL - OverviewDTTB into PAL - Overview

DVB-T marginally less interference to PALDVB-T marginally less interference to PAL

DTTB Co channel signals need to be kept DTTB Co channel signals need to be kept at least 46 dB on average below the at least 46 dB on average below the Wanted PAL level to ensure Grade 4 Wanted PAL level to ensure Grade 4 receptionreception

DTTB Adjacent channel signals need to be DTTB Adjacent channel signals need to be kept on average at or below the Wanted kept on average at or below the Wanted PAL level to ensure Grade 4 receptionPAL level to ensure Grade 4 reception

66

PAL into DTTB - ResultsPAL into DTTB - ResultsD T T B S y s t e m P a ra me te rs P A L in to D T T B P ro t e c t io n (D /U )

D T T B T YP E C O N S T ELLA T IO NM O D U LA T IO N

F EC C o d eR a te

C h 7 Lo w e rA d j C h (d B )

C o C h a n n e l(d B )

C h 9 U p p e rA d j C h (d B )

D VB -T -7 C O F D M Q P S K 1/2 -44.8 -13.0 -49.2

D VB -T -7 C O F D M Q P S K 2/3 -44.5 -8.4 -47.0

D VB -T -7 C O F D M Q P S K 3/4 -43.7 -4.0 -45.3

D VB -T -7 C O F D M Q P S K 5/6 -42.3 3.1 -43.3

D VB -T -7 C O F D M Q P S K 7/8 -40.8 9.7 -42.0

D VB -T -7 C O F D M 16-Q A M 1/2 -43.5 -8.8 -46.1

D VB -T -7 C O F D M 16-Q A M 2/3 -42.1 -2.3 -43.3

D VB -T -7 C O F D M 16-Q A M 3/4 -40.2 3.3 -41.2

D VB -T -7 C O F D M 16-Q A M 5/6 -37.0 9.9 -39.1

D VB -T -7 C O F D M 16-Q A M 7/8 -35.2 16.9 -37.3

D VB -T -7 C O F D M 64-Q A M 1/2 -41.2 -3.1 -41.7

D V B -T -7 C O FD M 6 4 -Q A M 2 /3 -3 5 .4 1 .4 -3 7 .5

D VB -T -7 C O F D M 64-Q A M 3/4 -35.0 10.8 -35.9

D VB -T -7 C O F D M 64-Q A M 5/6 -31.2 17.1 -33.1

D VB -T -7 C O F D M 64-Q A M 7/8 -28.9 22.6 -30.8

A T S C -6 8 -V S B 8 -A M 2 /3 -3 8 .6 9 .1 -3 8 .7

67

PAL into DTTB - Protection PlotPAL into DTTB - Protection PlotPal into DTTB Protection Ratio Comparison for 50 dBuV DTTB Signals

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

10

-8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8

8-VSB

COFDM


00

-10-10

-20-20

-30-30

-40-40

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1010

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68

Co Channel PAL into DTTB - PlotCo Channel PAL into DTTB - PlotDTTB Small Frequency Offset Co-channel Pal protection for 50 dBuV DTTB Signals

-5

0

5

10

15

-40 -30 -20 -10 0 10 20 30 40

8-VSB Pal Co-Channel Protection

COFDM V2.1 EQ Pal Interference

8-VSB Co ChannelCOFDM Co Channel

00-10-10-20-20-30-30-40-40 1010 2020 3030 4040Frequency Offset (kHz)Frequency Offset (kHz)

00

55

1515

-5-5

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1010

69

Off Air PAL into DTTB - PlotOff Air PAL into DTTB - PlotPal into DTTB Protection with real Off Air Pal signals either side of DTTB Channel 8

Note: Channel 7 only has a single monophonic Sound

carrier which is 10 dB below the Vision carrier level

-40

-35

-30

-25

-20

-15

-10

-5

0

5

-2000 -1500 -1000 -500 0 500 1000 1500 2000

7 MHz COFDM

6 MHz 8VSB

00

-10-10

-20-20

-30-30

-40-40

-35-35

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55

-5-5

-15-15

-25-25

00-0.5-0.5-1-1-1.5-1.5-2-2 11 220.50.5

Channel 8 DTTB Frequency Offset (MHz)Channel 8 DTTB Frequency Offset (MHz)

1.51.5

6 MHz 8-VSB7 MHz COFDM

70

DTTB & PAL in Adjacent ChannelsDTTB & PAL in Adjacent Channels

0 dB Relative Levels - PAL/DTTB0 dB Relative Levels - PAL/DTTB

COFDM PAL COFDM

71

PAL into DTTB - Overview 1PAL into DTTB - Overview 1

The narrower ATSC system achieves very The narrower ATSC system achieves very similar out of band / adjacent channel similar out of band / adjacent channel performance to DVB-T.performance to DVB-T.

ATSC is nearly 8 dB worse than DVB-T ATSC is nearly 8 dB worse than DVB-T when subjected to interference from Co-when subjected to interference from Co-Channel PAL transmissionsChannel PAL transmissions

72

PAL into DTTB - Overview 2PAL into DTTB - Overview 2

In situations where Co-Channel DTTB and In situations where Co-Channel DTTB and PAL signals exist the DTTB into PAL PAL signals exist the DTTB into PAL interference will be the dominant factor, interference will be the dominant factor, providing directional antennas are used.providing directional antennas are used.

If a DTTB frequency offset was being If a DTTB frequency offset was being considered for use, the data indicates that considered for use, the data indicates that moving up in frequency is preferable to moving up in frequency is preferable to moving down.moving down.

73

CW into DTTB - Protection PlotCW into DTTB - Protection PlotCW Interferer into DTTB Protection Ratio Comparison for 50 dBuV DTTB Signals

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

10

15

-8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8

8-VSB

COFDM


00

-10-10

-20-20

-30-30

-40-40

-50-50

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8-VSBCOFDM

74

CW into DTTB - SummaryCW into DTTB - Summary

DVB-T is on average 15.5 dB less sensitive DVB-T is on average 15.5 dB less sensitive across the channel to general CW type across the channel to general CW type interferers than ATSCinterferers than ATSC

The DVB-T orthogonal carrier spacing is The DVB-T orthogonal carrier spacing is evident for DVB-T in this measurement with evident for DVB-T in this measurement with a variation of over 8 dB. If known CW a variation of over 8 dB. If known CW interferers are likely then a frequency offset interferers are likely then a frequency offset of less than 4 kHz may assist system of less than 4 kHz may assist system performance.performance.

75

CW into DTTB centre channelCW into DTTB centre channelDTTB Small Frequency Offset Co-channel CW Interference protection for 50 dBuV Signal

-10

-5

0

5

10

15

-40 -30 -20 -10 0 10 20 30 40

8-VSB CW Interference Protection

COFDM V2.1 EQ CW Interference

8-VSB CW ProtectionCOFDM CW Protection

00

55

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1010

1515

-10-1000-10-10-20-20-30-30-40-40 1010 2020 3030 4040

Frequency Offset (kHz)Frequency Offset (kHz)

76

CW into DTTB - CommentCW into DTTB - Comment

ATSC has occasional peaks due to critical ATSC has occasional peaks due to critical equaliser responses.equaliser responses.

The DVB-T response above was obtained The DVB-T response above was obtained from the improved equaliser which was from the improved equaliser which was provided near the end of the tests.provided near the end of the tests.

77

DTTB into DTTB - OverviewDTTB into DTTB - Overview

D T T BT Y P E

C h 7 L o w e rA d j C h (d B )

C o C h a n n e l(d B )

C h 9 U p p e rA d j C h (d B )

D V B -T -7 -2 8 .3 2 0 -2 8 .5A T SC -6 -3 0 .4 1 4 .6 -3 2 .2

Adjacent channel performance of ATSC is better Adjacent channel performance of ATSC is better than DVB-Tthan DVB-T

The Co-channel protection of both digital The Co-channel protection of both digital systems approximates to the system carrier to systems approximates to the system carrier to noise threshold.noise threshold.

78

DTTB into DTTB - Protection PlotDTTB into DTTB - Protection PlotDTTB into DTTB Protection

-35

-30

-25

-20

-15

-10

-5

0

5

10

15

20

25

-8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8

COFDM

8-VSB

00-1-1-2-2-3-3-4-4-5-5-6-6-7-7-8-8 11 22 33 44 55 66 77 88Frequency Offset of Unwanted DTTB (MHz)Frequency Offset of Unwanted DTTB (MHz)

00

-10-10

-20-20

-30-30

2020

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8-VSBCOFDM

79

DTTB Field Testing ObjectivesDTTB Field Testing Objectives

Investigate the difference in reception character Investigate the difference in reception character for the two DTTB modulation systems.for the two DTTB modulation systems.

Provide information to DTTB system plannersProvide information to DTTB system planners To provide Credible data.To provide Credible data.

A DTTB Field Trial is study of Failure !!A DTTB Field Trial is study of Failure !!In comparison with current PAL television

In various reception conditions :

80

Field Testing - VanField Testing - Van A field test vehicle was built in a small van.A field test vehicle was built in a small van.

81

Field Testing - On the StreetsField Testing - On the Streets Over 115 sites were measuredOver 115 sites were measured

82

Field Test Vehicle Block DiagramField Test Vehicle Block DiagramField Test Vehicle Block DiagramField Test Vehicle Block Diagram

NoiseNoiseSourceSource

55waywaysplitsplit

SpectrumSpectrumAnalyserAnalyser

Plisch PALPlisch PALDemodulatorDemodulator

DVB-TDVB-TReceiverReceiver

ATSCATSCReceiverReceiver

Vector SignalVector SignalAnalyserAnalyser

BERBERMeterMeter

CROCRO

PALPALMonitorMonitor

VM-700VM-700

-20dB-20dB

11.5 dB11.5 dB

11.5 dB11.5 dB

NF 3.6 dBNF 3.6 dB

-7 dB-7 dB

InputInputlevellevel

NoiseNoiseInjectionInjection

Ch 6-11 VHFCh 6-11 VHFAntenna onAntenna ona 10 m Masta 10 m Mast

83

Field Testing - MethodField Testing - Method Field tests were conducted in Sydney over a Field tests were conducted in Sydney over a

1 month period on VHF channel 8. 1 month period on VHF channel 8. Some simultaneous tests were conducted on VHF Some simultaneous tests were conducted on VHF

channel 6channel 6 Power level for the field test was 14 dB below Power level for the field test was 14 dB below

adjacent analog television channels 7 & 9 adjacent analog television channels 7 & 9 Analog and digital television performance for both Analog and digital television performance for both

systems were evaluated at each site.systems were evaluated at each site. Conducted by Independent Consultant & Mr Wayne Conducted by Independent Consultant & Mr Wayne

Dickson of TENDickson of TEN

84

Field Test - Data Collected each SiteField Test - Data Collected each Site

Common Masthead Amp used (NF ~ 3.6 dB)Common Masthead Amp used (NF ~ 3.6 dB) Analog PAL transmission character (7,9 & 10)Analog PAL transmission character (7,9 & 10) Measure level, multipath, quality & Video S/NMeasure level, multipath, quality & Video S/N Measure DVB & ATSC reception (Ch 8)Measure DVB & ATSC reception (Ch 8) Record DTTB & Analog SpectrumRecord DTTB & Analog Spectrum Measure Noise Margin (C/N Margin)Measure Noise Margin (C/N Margin) Measure Level Threshold (Signal Margin)Measure Level Threshold (Signal Margin) Measure antenna off pointing sensitivityMeasure antenna off pointing sensitivity

85

0

5

10

15

20

25

30

35

40

Sit

e R

EC

EIV

E M

AR

GIN

(d

B)

45 50 55 60 65 70 75 80 85 90 95 100 105 110

Site Field Strenght (dBuV/m)

PAL - SITE RECEIVE MARGINFacts DTTB Trial Sites

PAL on CH9

Plisch Receiver

W.T.D. 5 JUNE 1998

Nominal conditions : 7 dB gain Antenna + 2 dB leed loss @ CH9

MINIMUM ACCEPTABLE PICTURE

Minimum F/S = 55dBuV/m

Margin to minimum acceptablepicture w/o multipath

for HIGH GAIN ANTENNA

Receiver limitations

Effective decoder Noise Figure (NF) = 5 dB

Australian DTTB Field Trial PAL Receive Margin

Australian DTTB Field Trial PAL Receive Margin

86

Australian DTTB Field Trial DTTB compared to PAL

Australian DTTB Field Trial DTTB compared to PAL

-45

-40

-35

-30

-25

-20

-15

Vid

eo S

/N

of PA

L @

D

TTB

TH

RE

SH

OLD

(d

B)

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115

TEST #

PAL VIDEO S/N @ DTTB THRESHOLD@ 14dB nominal DTTB to PAL ratio

System Noise Method

8VSB

COFDM (64QAM,2/3,1/8)

Note : 8VSB Launch power on average was 0.8dB higher than COFDM Launch power

Average S/N @ Threshold of :8VSB = -24.2dB unwtd (PAL)COFDM = -28.7dB unwtd (PAL)

FACTS DTTB Trial Sites

W.T.D. 15 Jan 1998

87

Australian DTTB Field Trial 8VSB Decoder Margin

Australian DTTB Field Trial 8VSB Decoder Margin

0

10

20

30

40

50

60

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GIN

(dB

)

25 30 35 40 45 50 55 60 65 70 75 80 85 90


8VSB SITE DECODE MARGINFACTS DTTB Trial Sites

8VSB

System Noise MethodW.T.D. 7 JUNE 1998

Nominal conditions : 7 dB gain Antenna + 2 dB leed lossEffective decoder Noise Figure (NF) = 9 dB

NO PICTURE

Minimum F/S = 37 dBuV/m

without multipath

and 3 dB margin

Margin @ Threshold C/N

w/o multipath

Decoder NF = 9 dB

for a HIGH GAIN ANTENNA


with multipath allowance

and 3 dB marginMargin @ threshold C/N

with multipath

88

Australian DTTB Field Trial COFDM Decoder Margin

Australian DTTB Field Trial COFDM Decoder Margin

0

10

20

30

40

50

60 Sit

e D

EC

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AR

GIN

(dB

)

25 30 35 40 45 50 55 60 65 70 75 80 85 90


COFDM SITE DECODE MARGINFACTS DTTB Trial Sites

COFDM (64QAM,2/3,1/8)

System Noise Method

W.T.D. 5 JUNE 1998

Nominal conditions : 7 dB gain Antenna + 2 dB leed loss @ CH8

Effective decoder Noise Figure (NF) = 5 dB

NO PICTURE


without mutipath

and 3 dB margin

Margin @Threshold C/N

w/o multipath

Decoder NF = 5 dB

for a HIGH GAIN ANTENNA


with multipath allowance

and 3 dB marginMargin @ Threshold C/N

with Multipath

89

VHF - Band IIIVHF - Band III

UHFUHF

DOPPLERDOPPLERSHIFTSHIFT((Hz)Hz)

140 140

300300

0000 10001000500500100100 200200 300300 400400 600600 700700 800800 900900

100100

5050

200200

250250

COFDM 2K, 3dB degradeCOFDM 2K, 3dB degrade

COFDM 2KCOFDM 2K

SPEED (Km/Hr)SPEED (Km/Hr)AIRCRAFTAIRCRAFTVehiclesVehicles

Over CitiesOver Cities

for currentfor currentimplementationsimplementations

ATSCATSCseesee separateseparate curvescurves

COFDM implementations will inherently handleCOFDM implementations will inherently handle post andpost and pre-ghostspre-ghosts equally within the selected guard interval.equally within the selected guard interval.

DTTB Systems Doppler Performance LimitsDTTB Systems Doppler Performance Limits

90

VHF - Band IIIVHF - Band IIIUHFUHF

0000 100100

8VSB, “Fast Mode”, 3dB degrade8VSB, “Fast Mode”, 3dB degrade

SPEED (Km/Hr)SPEED (Km/Hr)

VehiclesVehicles

8VSB8VSB

55

1

1010

3030232310106622

AircraftAircraft

for current for current implementationsimplementations

8VSB implementations of equalisers are likely to cater for8VSB implementations of equalisers are likely to cater for post ghostspost ghosts up toup to 30 uSec30 uSec andand pre-ghostspre-ghosts up toup to 3 uSec 3 uSec onlyonly..

DOPPLERDOPPLERSHIFTSHIFT((Hz)Hz)

ATSC 8-VSB Doppler Performance LimitsATSC 8-VSB Doppler Performance Limits

91

Field Test - ObservationsField Test - Observations

At -14 dB DTTB power when there was a At -14 dB DTTB power when there was a reasonable PAL picture both 8-VSB & COFDM reasonable PAL picture both 8-VSB & COFDM worked at the vast majority of Sitesworked at the vast majority of Sites

When PAL had:When PAL had: Grain (noise) and some echoes (multipath), Grain (noise) and some echoes (multipath),

both 8-VSB & COFDM failedboth 8-VSB & COFDM failed Flutter, caused by aircraft or vehicles, 8-VSB failedFlutter, caused by aircraft or vehicles, 8-VSB failed Impulsive noise & some grain, COFDM failedImpulsive noise & some grain, COFDM failed

92

Results ConclusionResults Conclusion

The assessment of the results presented in The assessment of the results presented in this summary depends largely on the this summary depends largely on the SPECIFICSPECIFIC system system REQUIREMENTSREQUIREMENTS of the of the broadcaster and the viewers. broadcaster and the viewers.

The implementation and performance of The implementation and performance of both digital terrestrial transmission systems both digital terrestrial transmission systems are still being improved, however the are still being improved, however the DVB-T system shows more scope for DVB-T system shows more scope for achieving future advances.achieving future advances.

93

The Selection CommitteeThe Selection Committee

A selection committee was formed A selection committee was formed from FACTS ATV specialists group from FACTS ATV specialists group Representing:Representing: National broadcasters (ABC and SBS)National broadcasters (ABC and SBS) The commercial networks (7,9 & 10)The commercial networks (7,9 & 10) The regional commercial broadcastersThe regional commercial broadcasters The Department of Communications The Department of Communications

and the Artsand the Arts The Australian Broadcasting AuthorityThe Australian Broadcasting Authority

94

Selection Panel - ResponsibilitySelection Panel - Responsibility

Analysing the comparative tests and other Analysing the comparative tests and other available factual informationavailable factual information

Establishing the relevance of the Establishing the relevance of the performance differences to Australian performance differences to Australian broadcastingbroadcasting

Recommending the system to be usedRecommending the system to be used

95

Selection CriteriaSelection Criteria

Derived a set of 50 selection criteria Derived a set of 50 selection criteria relevant to the Australian transmission relevant to the Australian transmission environmentenvironment

Criteria were reduced to final 29 which Criteria were reduced to final 29 which could impact on the final decisioncould impact on the final decision

The criteria were weighted and an The criteria were weighted and an overall average used to rank the overall average used to rank the selection criteriaselection criteria

96

Selection Criteria - GroupsSelection Criteria - Groups

Most Important Criteria GroupingsMost Important Criteria Groupings CoverageCoverage System Design ElementsSystem Design Elements Operational Modes SupportedOperational Modes Supported Overall SystemOverall System ReceiversReceivers

97

Selection Criteria - AnalysisSelection Criteria - Analysis

Assessed each of the selection criteria Assessed each of the selection criteria elements for each modulation systemelements for each modulation system

Some criteria were put aside as it was Some criteria were put aside as it was felt there was not enough information felt there was not enough information to factually score those criteria to factually score those criteria

98

Criteria - CoverageCriteria - Coverage

Inner and outer service areasInner and outer service areas Performance with Roof top antennasPerformance with Roof top antennas Performance with Set top antennas Performance with Set top antennas ** Co-channel & Adjacent channel protectionCo-channel & Adjacent channel protection Mobile Reception Mobile Reception Multipath (Ghosting, Doppler & Flutter)Multipath (Ghosting, Doppler & Flutter) Immunity to impulse noiseImmunity to impulse noise

99

Criteria - System Design ElementsCriteria - System Design Elements

Combining & use of common Tx AntennaCombining & use of common Tx Antenna Requirements for implementing translatorsRequirements for implementing translators Suitability for co-channel translatorsSuitability for co-channel translators Ability to use existing transmittersAbility to use existing transmitters

100

Criteria - Operational Modes SupportCriteria - Operational Modes Support

HDTV SupportHDTV Support Support for closed captioningSupport for closed captioning Multiple languages AudioMultiple languages Audio Surround Sound Audio SystemSurround Sound Audio System

101

Criteria - Overall SystemCriteria - Overall System

Accepted HDTV systemAccepted HDTV system Performance within 7 MHz channelPerformance within 7 MHz channel Number useful Mb/s in 7 MHzNumber useful Mb/s in 7 MHz Ability to fit in existing infrastructureAbility to fit in existing infrastructure Overall Modulation System DelayOverall Modulation System Delay System Flexibility, Upgrade Capacity & System Flexibility, Upgrade Capacity &

Future Development CapacityFuture Development Capacity

102

Selection Criteria - ReceiversSelection Criteria - Receivers

Availability (for HDTV) MP@HLAvailability (for HDTV) MP@HL Receiver Features & CostReceiver Features & Cost PAL and DTTB capability PAL and DTTB capability Degree of customizing for AustraliaDegree of customizing for Australia Receiver Applications SoftwareReceiver Applications Software Lock up timeLock up time Australian channel selectionAustralian channel selection

103

DTTB Choice Assessment Sheet GROUP1 – COVERAGE ATSC DVB IMPORTANCE

Element Group

Element Group 1

1.1 Percentage of A coverage pop. served

1.2 Percentage of B coverage pop. served

1.3 Set top antennas

1.4 Mobile reception

1.5 Co-channel performance

1.6 Adjacent channel performance

1.7 Multipath Performance

1.8 Immunity to electrical interference

1.9 Ability to be conveyed in MATV and cabled systems

GROUP 2 - SYSTEM DESIGN ELEMENTS ATSC DVB IMPORTANCE

Element Group

Element Group 2

2.1 Combining to use common transmit antennas

2.2 Ease of use and cost of implementing translators

2.3 Common channel translator capability

2.4 Ability to use existing transmitters

GROUP3 - OPERATIONAL MODES SUPPORTED ATSC DVB IMPORTANCE

Element Group

Element Group 3

3.1 HDTV support

3.2 Support for closed captions

3.3 Support for multilingual audio

3.4 Audio System

GROUP 4 - OVERALL SYSTEM ATSC DVB IMPORTANCE

Element Group

Element Group 4

4.1 Adoption of an accepted rather than unique (HDTV) system

4.2 Performance within 7 MHz channel

4.3 Number of useful Mbs/7MHz

4.4 Overall encode/decode delay

4.5 System upgrade & further development capability

GROUP 5 - RECEIVER ELEMENTS ATSC DVB IMPORTANCE

Element Group

Element Group 5

5.1 Receiver availability, features & cost

5.2 Receiver and STB MP @ HL

5.3 Receivers with both PAL and DTTB capability

5.4 Receivers not specific design for Australia

5.5 Receiver applications software

5.6 Receiver lock-up time

5.7 Ability to provide automatic channel selection for Australian channelling

Selection Criteria MatrixSelection Criteria Matrix

104

DTTB Choice Assessment Sheet GROUP1 – COVERAGE ATSC DVB IMPORTANCE

Element Group

Element Group 1

1.1 Percentage of A coverage pop. served

1.2 Percentage of B coverage pop. served

1.3 Set top antennas

1.4 Mobile reception

1.5 Co-channel performance

1.6 Adjacent channel performance

1.7 Multipath Performance

1.8 Immunity to electrical interference

1.9 Ability to be conveyed in MATV and cabled systems

GROUP 2 - SYSTEM DESIGN ELEMENTS ATSC DVB IMPORTANCE

Element Group

Element Group 2

2.1 Combining to use common transmit antennas

2.2 Ease of use and cost of implementing translators

2.3 Common channel translator capability

2.4 Ability to use existing transmitters

Key Selection CriteriaKey Selection Criteria

105

Selection Result - June 1998Selection Result - June 1998

The selection committee The selection committee unanimously selected the unanimously selected the 7 MHz DVB-T modulation 7 MHz DVB-T modulation system for use in Australiasystem for use in Australia

The criteria that were set aside would, The criteria that were set aside would, however, not have changed the selection however, not have changed the selection decisiondecision

106

Overall Selection InfluencesOverall Selection Influences A single system for All Free to Air BroadcastersA single system for All Free to Air Broadcasters Ability to meet Governments objectives for coverageAbility to meet Governments objectives for coverage Able to deliver the HDTV quality objectiveAble to deliver the HDTV quality objective Availability of consumer products at acceptable costsAvailability of consumer products at acceptable costs Solid support from proponentSolid support from proponent Interoperability with other digital video platformsInteroperability with other digital video platforms Confidence in the system meeting the business Confidence in the system meeting the business

objectivesobjectives

107

More SelectionsMore Selections Sub-committees formed to investigate:Sub-committees formed to investigate:

Service information data standardService information data standard Multichannel audio systemMultichannel audio system HDTV video production format HDTV video production format

July 1998 3 further recommendationsJuly 1998 3 further recommendations SI data standard be based on DVB-SISI data standard be based on DVB-SI AC3 multichannel audio is the AC3 multichannel audio is the

preferred audio encoding formatpreferred audio encoding format 1920/1080/50 Hz interlaced 1125 lines is the 1920/1080/50 Hz interlaced 1125 lines is the

preferred video production formatpreferred video production format

108

Frame Rate Video Format DecisionFrame Rate Video Format Decision Examined 50 or 60 Hz based video formatsExamined 50 or 60 Hz based video formats Decided to stay with 25/50 Hz system:Decided to stay with 25/50 Hz system:

40+ years of 50 Hz Archive program material40+ years of 50 Hz Archive program material Overseas production available in 50 or 60 HzOverseas production available in 50 or 60 Hz Down-conversion is required for Legacy RxDown-conversion is required for Legacy Rx Inappropriate to use incompatible frame rates Inappropriate to use incompatible frame rates

in the FTA broadcast community in the FTA broadcast community Production problems associated with 60 Hz Production problems associated with 60 Hz

image capture in a 50 Hz power environment image capture in a 50 Hz power environment Broadcast / Consumer Manufacturers assurance Broadcast / Consumer Manufacturers assurance

50 Hz equipment will be available 50 Hz equipment will be available

109

Australian Video FormatsAustralian Video Formats

Use of Progressive and Interlace video formats Use of Progressive and Interlace video formats The Format selected to suit program content.The Format selected to suit program content. Likely Video FormatsLikely Video Formats MP@HLMP@HL, ,

1920x1080/25P 1920x1080/25P Film Material Film Material 1920x1080/50I1920x1080/50I General Entertainment General Entertainment 720x576/50P 720x576/50P Sports Coverage Sports Coverage 720x576/50I 720x576/50I SDTV Program SDTV Program

MP@MLMP@ML

110

DTTB Implementation Notes:DTTB Implementation Notes:

Although SFNs are of interest in Australia they Although SFNs are of interest in Australia they will be of little use during the simulcast period.will be of little use during the simulcast period.

Use may be made of Dual Frequency Networks Use may be made of Dual Frequency Networks to increase spectrum efficiencyto increase spectrum efficiency

The channel frequency matrix will be adjusted The channel frequency matrix will be adjusted when Analog TV services cease. when Analog TV services cease.

Digital TV provides the capacity to repack the Digital TV provides the capacity to repack the television spectrum.television spectrum.

111

A Future Digital System ConceptA Future Digital System Concept

HypermediaIntegrated Receiver

Decoder (IRD)

MMDS

Satellite

Terrestrial

Cable

B-ISDNXDSL CD, DVD

DVC

Broadcast Interactivity

112

The EndThe End

Thank you for your attentionThank you for your attention

Any questions?Any questions?

1 australian dttb lab tests, methodology & results summary presentation by: neil pickford...

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