1. Digital TV: An Introduction Gregory Bensberg

2. UK DTT 81 Main and Relay Sites

3. CP5 Before

4. CP5 After

5. Current use of grouped aerials in the UK London Frequencies Manchester Frequencies

6. Digital Satellite Coverage DSAT Study: UK coverage map. Shadow regions due to terrain

7. Predicted UK Coverage DSAT Study Extrapolated UK coverage

8. UHF spectrum now - Winter Hill

9. 3 Conversion plan Convert 3 analogue networks for DTT 6 multiplexes - 3 PSB, 3 commercial Assume 16QAM rate 3/4 or 64 QAM Rate 2/3 for all muxes Support regional services Release 14 channels i.e. 32 chs retained

10. Post switchover - 3 conversions

11. Alois Bock’s notes

12. Basic video compression techniques

14. Motion estimation on source or reconstructed

15. Basic video compression techniques Layer 1

16. Basic video compression techniques Layer 2

17. Basic video compression techniques Layer 3

18. Basic video compression techniques Layer 4

19. Basic video compression techniques Example hierarchical ME

20. Basic video compression techniques Example exhaustive ME

21. Basic video compression techniques Computational cost of ME

22. Basic video compression techniques B frame predictions I frameB frame P frame Display order

23. Adrian Turner’s notes

24. Single Carrier QAM sin cos x x + Re(M(t)) Im(M(t)) f c Frequency Power Spectral Density f c 1/T s T s

25. Constellations (2) QPSK 2 bits/symbol M(n) = ±1 ±j 16 QAM 4 bits/symbol 64 QAM 6 bits/symbol

26. Mapping data to the constellation Example - Gray coded 16QAM 0000 0001 0011 0010 0100 0101 0111 0110 1100 1101 1111 1110 1000 1001 1011 1010

27. OFDM Time domainFrequency domain T S

28. 11... Generating OFDM (1) Frequency Domain Modulation Symbols (QPSK example) reimreim Time Domain Samples FFTFFT jj-j...............

29. Fast Fourier Transforms

30. The DVB-T pilot structure Modulated carrier (QAM) Scattered or Continual Pilot TPS carrier Frequency Time

31. Transport Streams and Service Discovery Guy Hirson, BroadLynx Limited guy@broadlynx.co.uk DTT course Guildford University 2005

32. Transport Stream MPEG: Program Specific Information (CAT, PAT, PMT, NIT (?)) Information for the decoder DVB: Service Information BAT, EIT, NIT, RST, SDT, TDT & TOT Information for the user and service Services (DVB speak) or Programs (MPEG speak) carrying Elementary streams Private CA data in Tables Other private data (in Tables, Elementary Streams, etc.)

33. Containers for data carriage MPEG table section PES Packets Transport Stream Packets Data Streams PSI: PAT, PMT & CAT SI: NIT, SDT, EIT DSM-CC MHP AIT Media Streams Video Audio Subtitles Legacy Teletext

34. Protecting the Packet headerpayload RS 188 bytes 204 bytes

35. Transport Stream Packet headerpayloadheaderpayloadheaderpayload Sync byte Transport Error Indicator Payload unit start indicator Transport priority PIDTransport Scrambling Control Adaptation Field Control Continuity Counter Adaptation Field 811124N213 Adaptation field length Discontinuity indicator Random access indicator ES priority indicator 5 flags Optional fields Stuffing bytes 811NN51 PCROPCRSplice countdown TS private data length adaptation field extension length 3 flagsOptional fields 42 8NN58 TS private data

36. TS packet PCR insertion in the multiplexer 27 MHz counter PCR 42 bit hdrpayloadhdrpayload hdr payloadhdrpayload TS packet Video timebase

37. TS packet PCR extraction in the demultiplexer 27 MHz counter PCR 42 bit hdrpayloadhdrpayload hdr payloadhdrpayload TS packet Video timebase (1Hz in 27MHz, 10ppb/s) compare 42 bit error filter Frequency control

38. PES packets for synchronised data headerpayloadheaderpayload Packet start code prefix Stream_idPES packet length Optional PES header PES packet data bytes 248NNN16 ‘10’PES priority Data alignment indicator Original or copy Stuffing bytes 2NN PES scrambling control copyrightflagsPES header data len Optional fields 2111188 PTS DTS ESCRES RateAdditional copy info 2 DSM Trick mode Previous PES CRC PES extension 2111188

39. TS packet PTS extraction 27 MHz counter PTS 42 bit hdrpayloadhdrpayload hdr payloadhdrpayload TS packet Video timebase compare 42 bit error filter Video Buffer Audio Buffer

40. MPEG sections Table idSection syntax indicator Private indicator Private section length 81121 N private data bytes 1 Table_id extension Current next indicator 16 Version number Section number Private data 5832 2 2 Last Section number CRC32 18

41. The guts of an Integrated Receiver/Decoder CPU CA Transport Audio Decode Video Decode GPU DAC PAL Encode RC Modem SC I/ODemodFEC 123 456 789

42. Networks, Bouquets, Services and Events TS 1 TS 2 TS 3 Network Bouquet Service Event

43. Programs and their components MPEG-2 Transport Stream Program 1Program 2Program nPSIDataElementary Stream 1 (Video) Elementary Stream 2 (Audio1) Elementary Stream n (Subtitles) CA

44. The inter-linking of PSI Tables and Programs Program 1 Program 2 Program n PAT ECM ES 1 ES 2 ES 3 ECM 3 ES 4 PMT (2) MPEG-2 TS CAS ID 1 CAS ID x CAT

45. Selecting a Service by Logical Channel Number CPU Transport DemodFEC 123 456 789 Program SI filters Retrieve BAT, SDT, EITs Build table of services SI Processing NIT=> list of services + tuning data SDT=> Service names EITs=> Event info Select “channel” Tune to TS Program PSI filters for PAT Retrieve PAT Program PSI filters for PMT Retrieve PMT Set up to retrieve A/V Video Decode Audio Decode

46. Selecting an Event Event Name Description Attributes Event Name Description Attributes Event Name Description Attributes Event Name Description Attributes Data from EIT database Service ID etc. Service selection Select from menu

47. Data Carousel DDB DII transaction_id mi DII transaction_id mi Block Module Group DSI transaction_id gi

48. 48 Digital Terrestrial Television: Domestic and MATV Reception Peter Barnett Consultant Tel: +44 (0)1794 341053 E-mail: peter.barnett@mandercom.co.uk www.dtg.org.uk

49. DTT reception Domestic MATVIRS

50. Typical UHF spectrum

51. Aerials Group A Analogue Digital CH21CH68 CH37 Group A Group B Group C/D Group E Group K Group W

52. Aerials Group W CH21CH68 Group A Group B Group C/D Group E Group K Group W

53. Aerials Group A Group B Group C/D Group E Group K Group W Pre-switchover Post-switchover

54. Receiver operating window 304050607080 Signal level (dB  V) Analogue signal Digital signal Difference in received levels Marginal operation

55. Effects of pre-amplifiers 304050607080 Signal level (dB  V) Analogue signal Digital signal Difference in received levels

56. Upgrading systems Digital Analogue

57. Channel changing in MATV systems

58. Intermodulation in amplifiers

60. LNB interference into DTT Low band High band 10.7GHz11.7GHz12.75GHz 0 950MHz2150MHz Local oscillator

61. UHF interference into satellite

62. Measurements A B C

63. University of Surrey DTT : An Overview Receivers (Hardware) Nov 2005 v2.0 Peter Lewis Philips Semiconductors Technology Center Southampton UK

64. Inside a ‘Set Top Box’ RF in from aerial Picture & Sound out to TV set Channel Decoding Stage Source Decoding Stage TunerDemodulator

65. Tuner Phase Noise 1116 Hz (8k) 4464 Hz (2k) NB Carrier Separation Phase noise spreads the carriers So they interfere with each other

66. Tuner Step Size ANALOGUEDIGITAL RF from VCRs etc is imprecise RF from digital TXs is precise but may be offset ± 1/6MHz Therefore a fine tuning resolution is needed Therefore a 1/6MHz tuning resolution is needed

67. The adjacent channel problem Chan N Chan N-1 Peak sync power total power in channel Up to 35dB !

68. Lower adjacent sound, and SAW profile Chan N WANTED DVB-T SIGNAL +10 dB +20 dB +30 dB 0 dB SAW IF Filter Profile FM soundNICAM sound (Levels plotted as though with 100kHz BW S/A)

69. Attenuation of NICAM by one SAW Chan N EFFECTIVE NICAM LEVEL WITHOUT ANY FILTERING EFFECTIVE NICAM LEVEL WITH ONE SAW FILTER WANTED DVB-T SIGNAL +10 dB +20 dB +30 dB 0 dB

70. The more distant channel problem Chan N-x Up to 50dB ! Chan N

71. SAW filter profile for distant channels Chan N-x Chan N

72. Interference from distant channels Chan N-x Chan N X X X X F1F1 F2F2 F4F4 F3F3

73. Traditional High Quality Front-End TUNER 2 SAW FILTERS 1st IF AMP 2nd IF Filter ? DOWN- CONVERTER & AGC AMP DEMODULATOR Gain control

74. Modern High Quality Front-End TUNER IF / AGC AMP, in tuner Single SAW, in tuner DEMODULATOR, containing digital filtering that replaces one SAW filter Gain control

75. Channel decoder stage - demod IC TunerIF filter Local Oscil. 1st IF (~36MHz)2nd IF (~5MHz) Down conversion IC NB Down conversion is optional. Gain control is not ! DVB-T Channel demodulator & decoder IC ADC Digital front end FFT Chan est. & correct. Error Correct. Etc. Transport stream RF AGC amp

76. Channel decoder stage - digital F/E TunerIF filter Local Oscil. 1st IF (~36MHz)2nd IF (~5MHz) Down conversion IC NB Down conversion is optional. Gain control is not ! DVB-T Channel demodulator & decoder IC ADC Digital front end FFT Chan est. & correct. Error Correct. Etc. Transport stream RF AGC amp

77. Process that may be in the ‘Digital Front End’ Digital Frequency Adjustment ADC Digital AGC AGC detector analogue or digital IF correction required Gain control to RF/IF stages I & Q data at baseband  shift  =  correction x t data indata out

78. One method of identifying the symbol start correlation one full symbol guard interval threshold current sample futurepast TuTu TuTu

79. Channel decoder stage - FFT TunerIF filter Local Oscil. 1st IF (~36MHz)2nd IF (~5MHz) Down conversion IC NB Down conversion is optional. Gain control is not ! DVB-T Channel demodulator & decoder IC ADC Digital front end FFT Chan est. & correct. Error Correct. Etc. Transport stream RF AGC amp

80. Conversion from time samples to frequency values. frequency 2048 complex values for ‘2k’ 8192 complex values for ‘8k’ I -32 95 32 133 95 -32 32 -95 32 133 95 -32 133 Q 95 -95 95 0 32 95 32 -95 0 95 32 95 0 time 2048 complex values for ‘2k’ 8192 complex values for ‘8k’ Q -30 -70 12 69 80 10 64 70 10 -78 -30 -9 I 20 -90 78 56 40 12 -56 -40 20 80 90 -49 10 62

81. FFT window timing error ideal FFT window actual FFT window freq component  A freq component  B one full symbol guard interval timing error, t err phase error = t err x  A phase error = t err x  B

82. OFDM demod. stage - time corrector Digital Time Adjustment FFT  shift  = t correction x  data indata out The principle is the same as for frequency adjustment in the frequency domain I & Q time data I & Q frequency data

83. Channel decoder stage - Chan. est. & corr. TunerIF filter Local Oscil. 1st IF (~36MHz)2nd IF (~5MHz) Down conversion IC NB Down conversion is optional. Gain control is not ! DVB-T Channel demodulator & decoder IC ADC Digital front end FFT Chan est. & correct. Error Correct. Etc. Transport stream RF AGC amp

84. Echoes and Pilots Phase of echo Effect of echo Only first 200+ carriers shown. Continues on …. echo adds echo subtracts Continual PilotScattered Pilot Example of single echo with 1 usec delay

85. Channel estimation from pilots interpolate through time interpolate through frequency symbol N symbol N+1 symbol N+2 symbol N+3 to get estimates of channel response for every carrier scattered pilot

86. Channel equalisation Channel Estimation frequency data corrupted by channel, etc., effects frequency data corrected CPE Detection confidence

87. CPE detection Channel Estimation frequency data corrupted by channel, etc., effects frequency data corrected CPE Detection confidence

88. Common Phase Error - CPE Phase Error Time one symbol phase noise mixer local oscillator part of tuner RFIF +1kHz-1kHz example of cause

89. CPE Detection using continual pilots Continual Pilots mean = CPE symbol N symbol N + 1 etc... phase change between symbols etc...

90. CPE detection Channel Estimation frequency data corrupted by channel, etc., effects frequency data corrected CPE Detection confidence

91. Channel decoder stage: de-mapping, de- interleaving & error correction TunerIF filter Local Oscil. 1st IF (~36MHz)2nd IF (~5MHz) Down conversion IC NB Down conversion is optional. Gain control is not ! DVB-T Channel demodulator & decoder IC ADC Digital front end FFT Chan est. & correct. Error Correct. Etc. Transport stream RF AGC amp

92. Stages of ‘Error Correction Etc’ DVB-T Channel demodulator & decoder IC ADC Digital front end FFT Chan est. & correct. Error Correct. Etc. Transport stream de-mapping, de-interleaving, etc. de-coding

93. De-mapping, etc, stage de-mapping, de-interleaving, etc. de-coding

94. What is the basic job to be done? DE-MAPPING, DE- INTERLEAVING, etc. MAIN INPUT IS I & Q DATA STREAMS REPRESENTING THE MODULTION ON ALL THE USEFUL DATA CARRIERS I Q confidence MAIN OUTPUT IS A BITSTREAM WITH CONFIDENCE INFO. data

95. de- mapper symbol* de- interleaver bit de- interleaver De-mapping & Inner De- interleaving: mux data I Q confidence confid- ence order may be reversed * data on each carrier (not OFDM symbols)

96. de- mapper symbol de- interleaver bit de- interleaver demapper mux data I Q confidence confid- ence

97. Mapping: 16QAM example Each point represents 4 bits A, B, C, D A=0 B=0 D=0 C=0 Note that crossing one boundary changes only one bit C=1 D=1 A=1 B=1 e.g. ‘0,0,1,1’ I Q

98. 1,0,0,1 1,1,1,0 0,0,0,0 0,1,1,0 Demapping, to symbol vectors Simple Symbol Value Vector I Q I Q I Q I Q carrier n carrier n+1 carrier n+2 carrier n+3 etc.

99. 1(110), 0(101), 0(011), 1(001) Demapping, including confidence Full Symbol Metrics Vector I Q Bit values Confidence in each bit carrier n

100. 1 (100), 1, 0 (111)(010)(110) 0, 0 (110)(101), 0 0 (011), 1, 0 (111)(100)(111), 1 Demapping: separating vectors to metric streams Symbol Vector Value (Confidence) 1 0 0 111111 010010 110110 100100 1 1 1 0 110110 101101 101101 110110 0 0 0 0 111111 100100 111111 011011 0 1 1 0 stream 0 stream 1 stream 2 stream 3 1 (110), 0, 1 (101)(011)(001) 1 (100), 1, 0 (111)(010)(110) 0, 0 (110)(101), 0 0 (011), 1, 0 (111)(100)(111), 1 101101 011011 001001 110110 1

101. de- mapper symbol de- interleaver bit de- interleaver demapper mux data I Q confidence confid- ence 10101111 10001111 11000111 11101111 x 2, 4, or 6 1Data Confidence

102. de- mapper symbol de- interleaver bit de- interleaver Symbol de-interleaver mux data I Q confidence confid- ence 10101111 10001111 11000111 11101111 1Data Confidence x 2, 4, or 6

103. ‘Symbol’ de-interleaving 1512 or 6048 metrics de-interleaved to undo the corresponding process at the transmitter. metrics (data + confidence) for one complete OFDM symbol de- interleaved into original order metrics (data + confidence) for one complete OFDM symbol as received from de-mapper

104. de- mapper symbol de- interleaver bit de- interleaver Symbol de-interleaver mux data I Q confidence confid- ence 10101111 10001111 11000111 11101111 1Data Confidence 10111000 10111000 11010101 11111101 re-arranged x 2, 4, or 6

105. de- mapper symbol de- interleaver bit de- interleaver mux data I Q confidence confid- ence 10111000 10111000 11010101 11111101 x 2, 4, or 6

106. Bit de-interleaving, e.g. substreams 0 & 1. 000119202122404142436162636482838485103104105106124125... 000119202122404142436162636482838485103104105106124125... 000119202122404142436162636482838485103104105106124125... 000119202122404142436162636482838485103104105106124125... i/p stream 0 (bits b 0,0 - b 0,125 ) o/p stream 0 (bits a 0,0 - a 0,125 ) i/p stream 1 (bits b 1,0 - b 1,125 ) o/p stream 1 (bits a 1,0 - a 1,125 )

107. de- mapper symbol de- interleaver bit de- interleaver mux data I Q confidence confid- ence 10111000 10111000 11010101 11111101 00101000 10101000 01101101 01010110 re-arranged more x 2, 4, or 6

108. de- mapper symbol de- interleaver bit de- interleaver multiplexer mux data I Q confidence confid- ence 10111000 10111000 11010101 11111101 2, 4, or 6 streams 01111101 01111100 11011011 11101111 10010101 10110000 11111101 00111011 01101100 01111110 01010011 11111110 1 stream

109. De-coding stage: de-mapping, de-interleaving, etc. de-coding

110. What is the basic job to be done? DECODING OUTPUT IS A TRANSPORT STREAM confidence MAIN INPUT IS A BITSTREAM WITH CONFIDENCE INFO. data

111. convolutional inner decoder outer de- interleaver block outer decoder De-coding sub-stages: energy dispersal removal data confid- ence MPEG2 t/s (Viterbi)(RS) BER less than 2 x 10 -4 BER near zero

112. convolutional inner decoder outer de- interleaver block outer decoder Convolutional Decoder (Viterbi): energy dispersal removal data confid- ence MPEG2 t/s 10010011 01100100 11100110 01011011 01111111

113. Convolutional coding used in DVB-T 1 bit delay + + switches at twice input bit rate 1 bit delay INPUT BIT STREAM FINAL OUTPUT BIT STREAM (twice rate of input) Modulo 2 adder X OUTPUT BIT STREAM Y OUTPUT BIT STREAM

114. A simple convolutional coder + switches at twice input bit rate 1 bit delay INPUT BIT STREAM FINAL OUTPUT BIT STREAM (twice rate of input) Modulo 2 adder Y OUTPUT BIT STREAM X OUTPUT BIT STREAM

115. Example output of simple convolutional coder Input Bits Output Bits 0010110010 1000110010 1 Y 1 Y 0000 YYXX 1 X 0 X 110010101011 YYYYYYXXXXXX Delayed Input Bits + +

116. Options for ‘correcting’ an error and get a valid sequence 00101100100011101011 00111100100010001011 00011100100001001011 00101100100011101011 00100100100011011011 00100000100011000011 Tx. 00101100100011001011 Rx. Opt. A Opt. B Opt. C Opt. D Opt. E YYYYYYYYYYXXXXXXXXXX

117. convolutional inner decoder outer de- interleaver block outer decoder Outer de-interleaver: energy dispersal removal data confid- ence MPEG2 t/s 10010011

118. Outer de-interleaving 204 byte TS like packets 204 byte blocks, but with bytes interleaved Fifo shift registers 1 byte per position No delay 17 bytes delay 2 x 17 bytes delay 3 x 17 bytes delay 11 x 17 bytes delay 17 complete ‘switch rotations’ per packet RS parity bytes are now grouped at the end of each block. Effectively the inverse of the interleaving process at the transmitter

119. convolutional inner decoder outer de- interleaver block outer decoder Output of Outer de- interleaver: energy dispersal removal data confid- ence MPEG2 t/s 10010011

120. convolutional inner decoder outer de- interleaver block outer decoder Input to Block decoder (Reed-Solomon): energy dispersal removal data confid- ence MPEG2 t/s 204 byte (corrupted ?) blocks

121. Reed-Solomon Error Correction for DVB RS inc. The Reed-Solomon error correction process can locate and correct up to 8 corrupted bytes in the block of 204 bytes 47,00,13,08,00,00,A3,C3,C0,00,00,23,74,F2,……,46,8A,9C,00,23,00,00,4C,…..,00,04,06,00,C0,00,34,42,B9,57,...,F5,9C,A3.

122. Possible Implementation of RS Error Corrector 47,00,13,08,00,00,A3,C3,C0,00,00,23,74,F2,……,46,8A,9C,00,23,00,00,4C,…..,00,04,06,00,C0,00,34,42,B9,57,...,F5,9C,A3. Syndrome Calculation Error Location Calculation Error Calculation Error Correction 47,00,13,08,00,00,A3,C3,C3,00,00,23,74,F2,……,46,8A,9C,00,37,00,00,4C,…..,00,04,7C,00,C0,00,34,42,B9,43,...,F7,9C,A3. Input Block Output Block Parity bytes no longer needed

123. convolutional inner decoder outer de- interleaver block outer decoder Output from Block decoder (Reed-Solomon): energy dispersal removal data confid- ence MPEG2 t/s 204 byte (corrupted ?) blocks 188 byte quasi error free blocks

124. convolutional inner decoder outer de- interleaver block outer decoder Energy dispersion removal: energy dispersal removal data confid- ence MPEG2 t/s

125. Channel Decoder Stage Summary TunerIF filter 1st IF (~36MHz) DVB-T Channel demodulator & decoder IC ADC Digital front end FFT Chan est. & correct. Error Correct. Etc. Transport stream RF AGC amp