World Analogue Television Standards and Waveforms

HE INFORMATION presented in this section has been compiled from several modern and historical sources and, errors and omissions excepted, the intention is to give a summary of the various standards at the time that they were current. Nevertheless, it is hoped that present-day standards are also accurately accounted for, and to this end any corrections would gratefully received (please E-mail me with any comments). Thanks are especially due to Mark Carver, Steve Palmano and Peter Vince for help and advice. Written sources consulted include [Electronics and] Wireless World and [Practical] Television magazines, textbooks by Benson KB and Whitaker JC, Carnt PS and Townsend GB, Holm WA, Hutson GH, Kerkhov F and Werner W, and technical publications from BBC, EBU, IBA and ITU.

I am particularly indebted to Peter Vince for recently spotting certain anomolies in the ITU document BT.470-6 from which many of the details in these pages were taken. It has been superseded by BT.1700 and BT.1701, and the values quoted in these pages are now verified by those, and by SMPTE 170M-1999 in relation to the NTSC standard. Many of the NTSC parameters feature recurring decimal fractions, and I have indicated these throughout with square brackets, for example f_SC = 3 579 545.[45]Hz

A discussion of the characteristics of the MAC (Multiplexed Analogue Component) satellite transmission systems is on the Colour Standards page.

Some systems are, or were, sometimes known by the standards organisations that developed or introduced them. Hence System M is often known as NTSC, Systems B, G and H as CCIR and Systems D, K and K1 as OIRT (after the Organisation Internationale de Radiodiffusion et Télévision in Prague, the Eastern Bloc equivalent of the EBU).

Key to abbreviations:

^Ob Obsolete line standard
Soundtracks:
M Mono (mono soundtrack in first language or L+R of stereo soundtrack)
S L-R of stereo soundtrack
N Mono soundtrack in second language, or subsidiary audio channel
L Left-hand stereo channel
R Right-hand stereo channel
D Data
Modulation modes:
AM Amplitude Modulation (A3E)
FM Frequency Modulation (F3E)
DQPSK Differentially-encoded Quadrature Phase Shift Keying
NICAM 728 Near-Instantaneously Companded Audio Multiplex at 728 kilobits per second

Notes:

The aspect ratio of all systems was standardised at 4:3 in 1952. However, there is evidence to suggest that the aspect ratio of System A (405 lines) was originally 5:4 and that of System E (819 lines) was 4.12:3.

System M has approximately 60 (actually 59.940 when carrying NTSC colour) interlaced fields per second (two 262.5-line fields make one 525-line frame). All other systems have precisely 50 interlaced fields per second (nominal). In most cases the field and line frequencies are usually derived from the colour subcarrier master oscillator, though in monochrome days the field frequency tended to be locked to the national mains supply, in order to avoid moving hum patterns on receivers. In System M timings may be derived from a 4.5MHz master oscillator (this is the same as the vision-sound spacing).

^[1] In New Zealand the sound-vision spacing is +5.4996 ±0.0005 and in Australia the tolerance may be +5.5 ±0.005.

^[2] The NICAM digital audio system has four options: stereo sound, dual language, mono sound + data, and just data, of which only the first two are generally used. It is also possible to transmit a different soundtrack from that on the main mono carrier, though that is rarely done.

^[3] System I-1 was adopted by those UK transmitters where a DVB-T multiplex had been introduced on the lower adjacent channel to an existing analogue allocation. The vestigial lower vision sideband of 0.75MHz offers reduced adjacent channel interference in comparison with the 1.25MHz of System I.

^[4] The French first programme was duplicated via low-power relays in black-and-white on 819 lines on System L uhf for a while, albeit with a reduced horizontal resolution compared to the vhf System E transmissions.

^[5] System L' is used for the Band I transmissions where the sound carrier is at -6.5MHz relative to the vision carrier instead of +6.5MHz as used in System L elsewhere.

^[6] In France, a digital carrier 5.85MHz away from the vision carrier may be used in addition to the main sound carrier. It is modulated in differentially encoded QPSK with a 728kbit/s sound and data multiplexer capable of carrying two sound channels. The nominal width of the main sideband is limited to 5.1MHz and the depth of video modulation in the radiated signal is reduced to leave a residual radiated carrier level of 5 ±2%.

^[7] In Belgium, in Systems C and F, AM sound was used with 50µs pre-emphasis.

Video and carrier levels

Notes:

^[1] Value applies to PAL signals.

^[2] Australia uses the nominal modulation levels specified for system I.

^[3] Italy is considering the possibility of controlling the peak white-level after weighting the video frequency signal by a low-pass filter, so as to take account only of those spectrum components of the signal that are likely to produce inter-carrier noise in certain receivers when the nominal level is exceeded.

^[4] In the Federal Republic of Germany, Austria, Italy, the Netherlands, Slovakia and Switzerland a system of two sound carriers is used, the frequency of the second carrier being 242.1875 kHz above the frequency of the first sound carrier. The ratio between vision/sound e.r.p. for this second carrier is 100/1. For stereophonic sound transmissions a similar system is used in Australia with vision/sound power ratios being 20/1 and 100/1 for the first and second sound carriers respectively.

^[5] In Denmark, Finland, New Zealand, Sweden and Spain a system of two sound carriers is used. In Iceland, Norway and Poland the same system is being introduced. The second carrier is 5.85 MHz above the vision carrier and is DQPSK modulated with 728 kbit/s sound and data multiplex. The ratios between vision/sound power are 20/1 and 100/1 for the first and second carrier respectively.

^[6] Studies in India confirm the suitability of a 20/1 ratio of effective radiated powers of vision and sound. This ratio still enables the introduction of a second sound carrier.

^[7] Values apply to SECAM signals. For programme exchange the value is 115.

^[8] In the People's Republic of China, the values 0 to 5 have been adopted.

^[9] The former USSR has adopted the value 15 ± 2%. A new parameter "white level with sub-carrier" is to be specified. For that parameter, the former USSR has adopted the value of 7 ± 2%.

^[10] In the People's Republic of China, the value 10/1 has been adopted.

^[11] The ratio 10/1 is used in the Republic of South Africa.

^[12] The ratio 20:1 is used in the United Kingdom. In the United Kingdom, a system of two sound carriers is used. The second sound carrier is 6.552 MHz above the vision carrier and is DQPSK modulated with a 728 kbit/s sound and data multiplex able to carry two sound channels. The ratio between vision and sound e.r.p. for the second carrier is 100/1.

^[13] In France, the ratios 10/1 and 40/1 are used. In France, a digital carrier 5.85 MHz away from the vision carrier may be used in addition to the main sound carrier. It is modulated in differentially encoded QPSK with a 728 kbit/s sound and data multiplexer capable of carrying two sound channels. The nominal width of the main sideband is limited to 5.1 MHz. With the L standard, the depth of video modulation in the radiated signal is reduced to leave a residual radiated carrier level of 5 ± 2%.

^[14] In Japan values 0 +10 -0 are used.

^[15] In Japan, the values of 0 to 6.75 have been adopted.

^[16] In Japan, a ratio of 1/0.15 to 1/0.35 is used. In the United States, the sound carrier e.r.p. is not to exceed 22% of the peak authorized vision e.r.p.

^[17] The values in brackets apply to the combination N/PAL used in Argentina.

^[18] The values in brackets are those listed in 1959 tables. Later tables show the video/sync ratio as 7/3 as for all other non-525-line standards.

HE FOLLOWING details are based on European Broadcasting Union transmitter lists and other publications from the early nineteen seventies, and include frequencies and line standards that have since been abandoned. Most countries have adopted uhf-only frequency plans in recent years, and of course many are in the process of closing down analogue services altogether, and in their place transmitting digital services in 8MHz-wide multiplexes on the existing uhf channel numbers.

• System A 405 lines 5MHz, United Kingdom until 2 Jan 1985, Republic of Ireland until 23 Nov 1982 (obsolete line standard)
  • For UK 405-line vhf transmitter lists, please visit my 405-lines page or the Wolfbane site.

• System B 625 lines 7MHz, East Germany until 1960s

Notes:

Transmitters were operational on the above channels in 1959. During the 1960s channels 1 to 3 were deleted and channels E3 to E12 adopted.

• System B 625 lines 7MHz, parts of western Europe (and East Germany from 1960s)
• System C 625 lines 7MHz, BRT Belgium (and RTB Belgium from 1960s) until 25 April 1977 (Ruiselede E2 transmitter continued until 1 April 1978)
• System F 819 lines 7MHz, RTB Belgium until February 1968, Luxembourg until 1 September 1971 (obsolete line standard)

Notes:

^[1] There has been no channel E1 allocation in Europe - see Missing Channels?.

^[2] E2A is identical to the OIRT allocation R1 and was used by an Austrian transmitter at Jauerling.

^[3] E4A is identical to the Italian allocation IC and was used by a few transmitters in other countries.

• System B 625 lines 7MHz, Italy

• System B 625 lines 7MHz, Australia

Notes:

^[1] Channels 3, 4, 5 and 5A were to due be cleared during 1993-96 to make way for FM radio stations in Band II.

^[2] New/amended channel allocations from 1993, replacing those in italics where appropriate.

• System B 625 lines 7MHz, New Zealand

• System B 625 lines 7MHz, Morocco

• System D 625 lines 8MHz, some Eastern Bloc countries

• System D 625 lines 8MHz, People's Republic of China

• System E 819 lines 14MHz, France until 1984, Monaco until 1985 (obsolete line standard)

Notes:

• System I 625 lines 8MHz, Republic of Ireland
  • For Republic of Ireland 625-line vhf transmitter lists, please visit the Wolfbane site.

• System I 625 lines 8MHz, Republic of South Africa

• System K1 625 lines 8MHz, French territories overseas

• System L 625 lines 8MHz, France, from 1985

Notes:

^[1] Channel L1 appears on some receivers, but nowhere else. No transmitters use it and it does not appear in allocation lists. See Missing Channels?.

^[2] Band I transmitters use System L' in which sound carriers are 6.5MHz below their respective vision carriers instead of above, as in System L.

• System M 525 lines 6MHz, The Americas

Notes:

^[1] Channel A1 was finally withdrawn on 14 June 1948 and allocated to fixed and mobile services - see Missing Channels?.

^[2] In Alaska and Hawaii channels 5 and 6 are allocated to non-broadcast services.

• System M 525 lines 6MHz, Japan

• System B 625 lines 7MHz, cable distribution, Belgium

• Systems B, D, G, I, K, L 625 lines 7/8MHz, cable distribution, Europe

Notes:

System B (7MHz channel spacing) is used on frequencies below 300MHz (S2-S20), and Systems D, G, I, K and L (8MHz channel spacing) on higher frequencies (S21-S37).

• System G 625 lines 7MHz, Australia

Notes:

^[1] Channel 27 is only 6MHz wide and therefore too narrow to accommodate a System G signal. Options are to increase the allocation to 7MHz or use the channel for data broadcasting.

^[2] Channels 69 and 69 will be allocated to other services when the analogue transmitters are closed down.

• System G 625 lines 8MHz, parts of western Europe, Africa, Asia, Australasia
• System H 625 lines 8MHz, Belgium
• System I 625 lines 8MHz, United Kingdom from 1964, Republic of Ireland, parts of Africa
  • For Republic of Ireland 625-lines uhf transmitter lists please visit the Wolfbane website.
  • For United Kingdom 625-lines uhf transmitter lists please visit the Wolfbane website.
  • Details of the United Kingdom uhf band plan are given below.
• System K, K1 625 lines 8MHz, French Territories overseas
• System L 625 lines 8MHz, France, Luxembourg

Notes:

In Germany, 525/60 stations operated by the American Armed Forces Radio and Television Service (AFRTS) have been allocated in "E" channels designated System G/NTSC with 4.5MHz v/s spacing.

In the UK, following the closure of analogue services, only channels E21 - E29 and E42 - E60 inclusive will be allocated for broadcast (DVB-T) use.

^[1] Channels E35 - E37 were not allocated in the UK until 1997 when the fifth terrestrial analogue chain (Channel 5, now known as 'five') began using E35 and E37. E35 was previously used for radio microphones.

^[2] Channel E38 is reserved for radio astronomy.

^[3] Channel E69 has rarely been allocated to a tv transmitter (a Swiss pay channel is one exception). It is reserved for use by broadcasters for their own internal purposes, for example radio microphones in television productions. The UK DTI approved the allocation for radio microphone use in 1992

• System M 525 lines 6MHz, Japan, most of The Americas and most territories with 60Hz mains supply
• System N 625 lines 6MHz, some South American countries

Notes:

^[1] In the USA channel A37 is reserved for radio astronomy.

^[2] In the USA frequencies 806-947MHz were reallocated for land-based mobile use from 1970.

hen the UK uhf 625-line television service began in 1964 it was envisaged that a network of transmitters would be set up to carry four programmes each. Each station would eventually carry all the services of the two incumbent broadcasters (BBC and ITA/IBA) on a "landlord/tenant" basis, alternating with each new installation. Since many of the first uhf stations would be built on exisiting ITA Band III sites they would continue to be the landlord there. At first only BBC2 was carried on uhf, then from 1969 the existing vhf 405-lines monochrome BBC1 and ITV services were duplicated in 625-lines PAL colour and from 1982 Channel Four was added. For some reason the mapping of programme to channel has not been in ascending order - ie BBC1, BBC2, ITV, C4 - at each transmitter. This would have made tuning (both manual and automatic) of receivers much easier.

Transmitting four high-powered signals from a single station is not an easy proposition. Because of the super-heterodyne system used in television receivers certain combinations of input frequencies can lead to interference, either in the same receiver or in nearby ones. With the intermediate frequencies and channel spacing used in Europe (vision 39.5MHz, sound 33.0/33.5/34.0MHz and 8MHz channel spacing) it can be shown that simultaneous signals on frequencies spaced five or nine channels apart should be avoided. (For the NTSC system, the 'forbidden' channels are plus or minus 2, 3, 4, 5, 7, 14 and 15.) This led to a set of nine available channel cluster patterns, each within a single aerial group, with the channels spaced at either N, N+3, N+6 and N+10 or N, N+4, N+7 and N+10.

Therefore only three sizes of aerial needed to be manufactured, and these were called Group A, marked red, channels 21-34, Group B, marked yellow, channels 39-51 and Group C, marked green, channels 52-68. As the network spread, however, it became necessary to depart from the nine clusters, and use a channel-spread greater than ten at some transmitters. Further aerial groups were added: Group D, marked blue, channels 49-68 and Group E, marked brown, channels 39-68. Group C was changed to cover channels 50-66 before Groups C and D were eventually merged to give Group C/D, marked green, channels 48-68. Group K, marked grey, channels 21-48, is used widely on the Continent, but also suits some UK situations.

When the fifth uhf network, Channel Five, began broadcasting in 1997, using mainly the previously vacant channels 35 and 37, aerial Groups A, B and E were enlarged so that all could receive those channels. Already, some four-channel transmitters required an aerial covering the whole of Bands IV and V (Group W, marked black) to be used, and the addition of Channel Five at some stations on channels well outside the original groups made their use more widespread, as did the introduction of DVB-T services on six extra channels that were slotted in willy-nilly in most areas without regard to existing receiving installations

During the 1990s the IBA's transmitter network was privatised and sold to National Transcommunications Limited (ntl:), and similarly the BBC's was later sold to Crown Castle International, clearly a group with an ironic sense of humour, since CCI (co-channel interference) is the bane of most broadcasters' lives.

Further shenanigans mean that ntl: is now known as Arqiva and CCI as National Grid Wireless (NGW).

Notes:

'Added': These channels have been added to extend the range of the groups at some time.

^[1] Originally announced as being marked for 'selling off' it appears that these channels may be allocated to commercial (pay tv?) broadcasters.

Analogue closedown 2008-2013

The right-hand column in the table above shows the channels (E21-E30 and E41-E62) that at the time of writing (September 2006) are expected to be available for DVB-T digital terrestrial transmissions following the closure of the System I analogue network, which is provisionally scheduled for completion in 2013. The remaining spectrum will probably be be reallocated on a national basis to other services, in much the same way that Bands I and III were in 1985, though they will continue to be used for broadcasting in adjacent countries. However, it appears that they could be allocated instead to commercial broadcasters for use by pay tv channels. As well as the initial six multiplexes in each region as mentioned below, there is now a seventh and eighth (and in Wales, a ninth) multiplex marked for commercial use. At some sites, channels in the range E31-E40 or E63-E68 are allocated for one or more of those extra multiplexes.

The current proposal from Ofcom is to close down the analogue service on a region-by-region basis beginning with The Borders in 2008 and finishing in 2013 with the Channel Islands, which currently do not have a DVB-T service because of frequency congestion. The idea is that regions bordering adjacent territories will be closed down last.

The plan is that in each new digital-only region there will be a set of six multiplexes, three for public service broadcasters (PSB1: BBC, PSB2: ITV/C4 and PSB3: BBC/five/S4C) and three (Com1-3) for commercial broadcasters. All 1154 present analogue sites will carry PSB1-3 and a maximum of 200 sites (to be decided by the broadcasters) will also carry Com1-3. The intention is that PSB1-3 will occupy three of the four current analogue channel allocations on each site so there will be no need to change aerials or communal distribution systems to receive them. In order to receive Com1-3 however, in some areas it will be necessary to erect a new aerial and/or modify communal aerial systems. Since the channels will be restricted to the regions E21-E30 and E41-E62, there will obviously be some existing analogue allocations that will not be available for the digital service and so some re-engineering at the transmitters will be necessary.

The conversion of all the stations in each region to digital-only working will probably last about six months, with the changeover at each main station and its dependants happening in two overnight operations a month apart. Firstly BBC2 analogue will close down and Mux 1 will be reincarnated as PSB1 in its new higher power allocation. At sites where the PSB1 allocation falls on a channel occupied by an analogue service other than BBC2 it will be necessary to shift the offending analogue service for a month to the old BBC2 channel to make way for PSB1. After a month all the old analogue and digital transmissions at the site will cease and the three or six new digital multiplexes will start up overnight on their final allocated channels.

It is anticipated that the effective radiated power (ERP) of the new multiplexes will generally be of the order of one-fifth the present peak analogue ERPs (twenty times the present digital ERPs) and that all multiplexes will use the original 64QAM (quadrature amplitude modulation) system (at the introduction of Freeview in 2002 Muxes 1, B, C and D changed to the more robust but lower capacity 16QAM). In addition, when the changeover to digital is complete in 2013, it is proposed to change transmissions from the 2k carrier system to the 8k system, which will improve performance and allow the use of single-frequency networks, although some very early digital receivers still in use will probably not work with it. It is expected that some additional fill-in sites may need to be introduced in order to match analogue coverage.

The changeover involves installing three or six new transmitters or translators at each main and relay station throughout the network, and new or modified aerials, masts or towers at some sites. All the dependants of each main station are planned to change on the same night as their parent, and several main stations have 50-75 dependants.

The above is a brief summary of the current situation, which is provisional and subject to ratification and possible amendment. Full, accurate and up-to-date information about the changeover is available on the Digital UK website. Digital UK is the non-profit-making organisation charged with planning and overseeing the change from analogue to digital working.

EOPLE OFTEN stop me in the street and ask why American and Continental European tellies don't have a 'channel 1' position. Now it can be told! There once was a US A1 channel (in fact there have been three), and there was an E1 (and an E1A) in Europe and an F1, but no L1, in France.

A1

This phantom channel had a brief but tortuous history:

• 1933 RCA set up an experimental station at W2XBS from the Empire State Building using 240 lines 24 frames per second progressive scan on 45MHz (vision carrier) with a 2MHz channel width using double sideband am sound and vision.
• 1934 Federal Communications Commission (FCC) was set up, and two vhf b