Catalog Sound and TV Broadcasting 2002/2003
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Standards 189 Contents Overview Chapter Overview Type Index R&S Addresses 12 Contents Page Page Basic standards Standards for digital video broadcasting (DVB) 199 International TV standards 190 MPEG2 and DVB data 203 Basic TV standards 191 Table of countries Broadcasting of TV programs 191 Systems and standards for monochrome and colour television/AC supply data 218 Dual-sound carrier systems 192 Group delay 221 TV broadcasting standards 193 Insertion test signals/colour-bar signals 224 Standards for monochrome television 194 Level patterns 225 Basic standards for colour television 195 Noise measurement/weighting filter 225 Broadcasting of special services 196 Channel definitions 226 Digital coding of colour TV video signals VHF 227 and sound signals 196 UHF 228 Satellite television and sound broadcasting 197 Abbreviations used Antiope Acquisition numérique et télévisualisation d´images FDM, TDM Frequency/Time Division Multiplex organisées en pages d´écriture GOST Standards system of the CIS (former USSR) BBC British Broadcasting Corporation GPO General Post Office CATV Cable Television IBA Independent Broadcasting Authority CBC Canadian Broadcasting Corporation ITU International Telecommunication Union CCETT Centre Commun d'Études de Télédiffusion et Télécom- (UIT) (Union Internationale des Télécommunications) munications ITU-R ITU Regulatory Sector (formerly CCIR) CCIR Comité Consultatif International des Radiocommunica- ITU-T ITU Technical Standards Sector (formerly CCITT) tions KtK Kommission für den Ausbau der technischen Kommu- CCITT Comité Consultatif International de Télégraphie et Télé- nikationssysteme phonie MAC Multiplex Analogue Component CEPT Conférence Européenne des Administrations des Postes NTSC National Television System Committee et des Télécommunications Didon Diffusion de données (par paquets) OIRT Organisation Internat. de Radiodiffusion-Télévision DIN Deutsches Institut für Normung PAL Phase Alternating Line SABC South African Broadcasting Corporation EBU (UER) European Broadcasting Union (Union Européenne de Radiodiffusion) SECAM Séquentielle à mémoire EIA Electronic Industries Association TDF Télédiffusion de France ERP Effective Radiated Power WARC World Administration Radio Conference FCC Federal Communications Commission Contents Overview Chapter Overview Type Index R&S Addresses Standards 190 Contents Overview Chapter Overview Type Index R&S Addresses Basic standards Field frequencies of 50 Hz and 60 Hz in reduced bandwidth) together with the conjunction with 500 lines to 600 lines luminance signal. Only two colour differ- International TV standards per frame led to a video frequency band ence signals are necessary (the third of more than 10 MHz. This was not being produced by electronic calculation Ten international TV standards exist at acceptable for the frequency channels in the receiver). present, all based on the same principles: available for TV transmitters and also ◆ Physiology of vision because of TV receiver technology and The two colour difference signals modu- ◆ Line scanning cost. An ingenious trick (F. Schröter, late a colour subcarrier – simultaneously ◆ Picture repetition 1927) cut the required frequency band with AM in the NTSC and PAL systems ◆ Colour transmission as separate lumi- down to half: interlaced scanning of a and successively with FM in the SECAM nance and chrominance components first field consisting of the odd lines and a system. The modulation frequency spec- second field consisting of the even lines trum of the colour subcarrier is inserted in Vision characteristics (illustration below). Thus a frequency of the frequency spectrum of the luminance ◆ Mean resolution 1´ (angle of sight) 50 fields/s (no flicker) and as little as 25 signal at the upper end of the video fre- ◆ Optimum angle for viewing without pictures/s (frequency band) were quency band (half-line or quarter-line off- fatigue of eye muscles 10° obtained. set). ◆ Optimum line number = viewing angle/angle of sight = 600 lines Colour transmission Observation of international TV standards ◆ Field frequency without motion Three colour TV systems were developed is necessary in view of ◆ blurred >12/s independently of each other regarding international exchange of programs, ◆ ◆ Field frequency without flicker >50/s the number of lines and field frequency: design of TV transmitters and trans- – NTSC 1948, posers, ◆ Number of lines per picture – PAL 1961, production of TV receivers, ◆ Pictures of 525 and 625 lines are still in – SECAM 1957. design of video recorders, ◆ use. Resolution being too weak with 405 The luminance signal is necessary for development of measuring instru- lines and the frequencies required being compatibility with the existing mono- ments and systems. too high with 819 lines, these two values chrome TV receivers. The three primary have been replaced by 625 lines. These signals red/green/blue are transmitted in "odd" line numbers originate from the the form of colour difference signals (with early times of television and are due to the frequency divider and multiplier tech- niques of the sync signal generators used in the past. Line 1st field 1 3 Field frequency Line The crucial factors were the limit of flicker 5 1 . and the AC supply frequency (50 or 2 3 . 60 Hz), since the early scanners (Nipkow 4 5 Line disc, Weiller wheel and film scanner) . 2 were all driven by AC supply-operated . 4 Interlaced scanning with synchronous motors. Hum bars resulting Frame . 50 fields (right) with 25 from inadequate filtering and other AC frames (left) line-frequency pickup were thus negligi- . ble. 2nd field Contents Overview Chapter Overview Type Index R&S Addresses Standards 191 Contents Overview Chapter Overview Type Index R&S Addresses 12 Basic TV standards ulated onto the other colour carrier. If Types of modulation only the colour system is to be converted, Vision: C3F (vestigial-sideband AM) ves- (Tables on pages 194 and 195) eg PAL into SECAM, the number of lines tigial-sideband ratios: Two basic standards have been adopted and the field frequency being equal, no 0.75 MHz/4.2 MHz = 1:5.6 for the international exchange of TV pro- picture memory is required. It then suf- 0.75 MHz/5.0 MHz = 1:6.7 grams: fices to separate and transcode the 1.25 MHz/5.5 MHz = 1:4.4 chrominance signal and to modulate the FCC standard CCIR standard new carrier as required (transcoder prin- The saving of frequency band is about Lines/frame 525 625 ciple). 40%; negative polarity because of the Fields/s 59.94 50 susceptibility to interference of the syn- Colour system NTSC PAL/SECAM Broadcasting of TV programs chronizing circuits of early TV receivers Video (exception: positive modulation); residual bandwidth 4.2 MHz 5/5.5/6 MHz carrier with negative modulation: 10% Colour The public television service is operated subcarrier 3.58 MHz 4.43 MHz by broadcasting picture and sound from (exception: 20%) picture transmitters and associated sound transmitters in three main fre- Sound: F3E; FM for better separation The different video bandwidths of the quency ranges in the VHF and UHF from vision signal in the receiver (excep- CCIR standard are not so much due to bands. By international ruling of the UIT/ tion: AM). field and line scanning procedures, but ITU, these ranges are exclusively allo- rather to the bandwidth available in the cated to television broadcasting. Subdivi- Sound carrier above vision carrier within TV transmitter channels (see broadcast- sion into operating channels and their RF channel, inversion at IF (exception: ing of TV programs below). assignment by location are also ruled by standard L in band I). international regional agreement. The The main problem of standards conver- Stockholm Plan of 1961 (table) is still valid sion is the conversion of field frequency in Europe: from 50 Hz to 59.94 Hz and vice versa. For this purpose, the picture information Band Frequency Channel Bandwidth must be stored and then scanned at the I (41) 47 MHz to 68 MHz 2 to 4 7 MHz new frequency. The previous electronic II 87.5 (88) MHz to 108 MHz VHF FM sound analog standards converter used the III 174 MHz to 223 (230) MHz 5 to 11 (12) 7 MHz screen of a high-resolution display tube IV 470 MHz to 582 MHz 21 to 27 8 MHz of suitable persistence and the display V 582 MHz to 790 (860) MHz 28 to 60 (69) 8 MHz was picked up like an open scene in the VI 10.7 GHz to 12.75 GHz satellite TV new standard by a camera. Special 68 MHz to 82 (89) MHz 2 (3) S channels 7 MHz channels DAB 113 MHz to 123 MHz S 2/3 5 MHz A digital standards converter converts the Cable TV 125 MHz to 174 MHz S 4 to S 10 7 MHz picture signal information from analog 230 MHz to 300 MHz S 11 to S 20 7 MHz into digital form, reads it into a digital 302 MHz to 470 MHz MAC 12 MHz memory, reads it out at a new scanning S 21 to S 41 8 MHz rate and reconverts it into analog form. In the standards converter for colour tele- vision, the incoming signal must be divided into its luminance and chromi- nance components, decoded and remod- Contents Overview Chapter Overview Type Index R&S Addresses Standards 192 Contents Overview Chapter Overview Type Index R&S Addresses Dual-sound carrier systems Channel 1 Channel 2 System parameters The two sound channels arrive from the (for standards B/G) RF sound carrier studio via radio link with 15 kHz band- width at the TV transmitter where matrix- Frequency fvision + 5.5 MHz fvision + 5.7421875 (±500 Hz), MHz (±500 Hz), ing is performed for compatibility: eqvt. to 352 fH eqvt. to 367.5 fH Vision/sound power 13 dB 20 dB – (L + R)/2 for channel 1, ratio – R for channel 2. Modulation FM FM ≤± ≤± Frequency deviation 50 kHz 50 kHz An additional sound modulator is used to µ µ Preemphasis 50 s 50 s modulate the second sound carrier with AF bandwidth 40 Hz to 15000 Hz 40 Hz to 15000 Hz sound channel 2 and with the AM-modu- Sound modulation lated pilot carrier.