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Synchrodyne
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Thanks for that Pieter.

I wonder if it was the case that the French engineers worked out what they calculated to be the best choice of IF channel and Band I channels for standard K1, but that receiver makers then chose to use more familiar numbers, such as the 32.7 MHz VIF, 39.2 MHz SIF and 39.9 MHz VIF, 33.4 MHz SIF combinations.

In Document 44-E of the ITU 1963 Geneva African VHF-UHF planning meeting, the French engineers mostly seemed to have worked from first principles.  Some testing was done with 32.7 MHz VIF, 39.2 MHz SIF, which was found to be problematical in Band I, and then with 39.9 MHz VIF, 33.4 MHz SIF, more-or-less as a starting point for the final set of calculations, from which 40.2 MHz VIF was selected.  Whether the Luxembourg case was considered is unknown, but it was not mentioned.

The CCIR and ITU-R documentation suggests that the alternative IFs for standard K1 may have come into use somewhat later on; they were not listed until 1992.  But against that, the CCIR and ITU-R reporting on IFs was often very post facto.  Once solid state technology dominated in domestic receivers, and particularly once IF strips were encapsulated in metal boxes similar to those used for tuners, the opportunities for harmful mutual interferences were probably reduced, allowing designers more flexibility where IF selection was concerned.

I know virtually nothing about African standard K1 receivers as such, so whether the multistandard type prevailed I don’t know.  I can imagine that receivers covering two or all of standards B/G/H, I and K1 might have been appropriate in some of the smaller countries.  And that there might have been a more general move to multistandard receivers in the IC and SAWF age, when they became easier to design and make.  I have no reason to suppose that African B/G/H receivers used other than the European standard IF of 38.9 MHz VIF, 33.4 MHz SIF (Australia appears to have been the only exception there).  South African standard I receivers used 38.9 MHz VIF, 32.9 MHz SIF.  So I think that more information is needed as to what actually happened in practice, which could well have been different to what was planned or envisaged.  What the SAWF makers did from the late 1970s and onwards could also be indicative.  I know that South African standard I SAWFs appeared quite early, but I’ll need to look again at the (limited) information on hand to see if there were any that were standard K1-specific.

The documentation for the ITU 1963 Geneva African VHF-UHF Conference is available here:

  https://www.itu.int/en/history/Pages/RadioConferencesRegional.aspx?conf=4.88

I have separated out some of the pertinent documents as separate .pdfs, including 44-E about the standard K1 IF development.  It is too big to attach here, but please send me a PM if you’d like me to email you a copy.

Before too long I should have ready a posting that comments upon the sequence of CCIR and ITU-R TV IF reports, which I have also separated out from the larger ITU and CCIR documents (from:  https://www.itu.int/en/history/Pages/ConferencesCollection.aspx ).

Cheers,

Steve

Mod Note: Post formatting corrected

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Topic starter Posted : 24/10/2018 8:22 am
Nuvistor
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I cannot contribute anything to this thread or the other on analogue transmissions but just to say I appreciate and enjoy the posts that members have contributed.

 

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Posted : 24/10/2018 9:43 am
Synchrodyne
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CCIR Plenary Meeting Intermediate Frequency Reports:

For a period, the documentation from the CCIR Plenary meetings included reports on receiver intermediate frequencies, including those for domestic TV receivers. There was a qualitative report (#41) from Warsaw 1956, with the first quantitative report (#98) being that from Los Angeles 1959. These reports were informative not normative, and by no means covered all of the major IF values in use. In some cases there were time delays between the adoption of a given IF and its inclusion in the CCIR reports. Presumably they relied upon voluntary reporting by the meeting participants. As well as narrative content, these CCIR reports also contained tabular data, which I have extracted. That is presented below in chronological order, with comments as appropriate.

A useful aspect of the CCIR TV IF reports was that as well as delineating the IFs in terms of VIF and SIF, they also showed the nominal IF channel limits, something not always done. In some cases, such as that of Italy, the limits of protection were the channel limits.

The complete originals of these reports may be found in the CCIR meeting documentation, available at: https://www.itu.int/en/history/Pages/ConferencesCollection.aspx, on a meeting-by-meeting basis. Some searching within the documents for individual meetings is required.

From CCIR Report #98, Los Angeles 1959:

CCIR 1959 Los Angeles Report 98 Intermediate Frequencies Table

As may be seen, the standard IFs then in use in each of the UK, USA, Japan, a group of Western European countries (Spain, Netherlands, Germany and Switzerland), Italy and USSR were recorded. Notably absent were the IFs for France and Australia. In fact, the Australian standard IFs never made it into any of the CCIR Reports. Japan and Italy were both shown as having protected TV IF channels.

The presentation of the Western European group suggests that although the 38.9 MHz VIF, 33.4 MHz SIF combination for the Gerber 625-line system was a recognized standard, the CCIR used inputs from the various in-country administrations, which in turn may have followed from either de jure or de facto recognition by appropriate bodies within those countries.

From CCIR Report #184, Geneva 1963:

CCIR 1963 Geneva Report 184 Intermediate Frequencies Table I

Here the French standard IFs for both the 819-line VHF and 625-line UHF cases have been added. The VHF case is shown as Band III, but in fact Band I was also used for 819-line transmissions. The channel limits show IF bandwidths of 14.4 MHz for the 819-line case and 8.5 MHz for the 625-line case. The original transmission channel width for the 819-line system was 14 MHz, although 13.15 MHz channel spacing was used for the definitive tête-bêche VHF channelling system. The French 625-line system was used in 8 MHz transmission channels, although the 8.5 MHz number was correct when conventional reckoning for guard bands was used.

From CCIR Report #184-1, Oslo, 1966:

CCIR 1966 Oslo Report 184 Intermediate Frequencies Table I

There were no changes in the tabular data.

From CCIR Report #184-1, New Delhi 1970:

CCIR 1970 New Delhi Report 184 1 Intermediate Frequencies Table I

There were several changes:

For Japan, a second, higher IF had been added, namely 58.75 MHz VIF, 54.25 MHz SIFin a protected channel. This was shown as being the IF for all-channel (VHF-UHF) receivers, whereas the older 26.75 MHz VIF, 22.25 MHz SIF combination was then shown as being for VHF receivers. The timing of its addition to the CCIR list appears to have been soon after its introduction.

Norway and Sweden were additions to the Western European group of countries.

For the USSR , a new IF, 38.00 MHz VIF, 31.50 MHz SIF, had replaced the earlier set. Whether this had happened somewhat before 1970 is unknown. It appears that ST61 channel allocation planning was done on the basis of two IFs, both the former standard and another set that would have been in the vicinity of 38 MHz VIF.

In the French case, both the VHF and UHF standards IFs were shown as now being covered by SCART Recommendation #103.

The UK standard UHF IF , 39.5 MHz VIF, 33.5 MHz SIF, was shown for the first time, even though it had been established in 1962.

From CCIR Report #184-2, Geneva 1974:

CCIR 1974 Geneva Report 184 2 Intermediate Frequencies Table I

Italy had changed to the standard Western European IF, namely 38.9 MHz VIF, 33.4 MHz SIF, shown as a protected channel. This change was apparently anticipated in the ST61 UHF allocation planning, as both the previous Italian standard and the European standard IFs were taken into account.

From CCIR Report #184-3, Kyoto 1978:

CCIR 1978 Kyoto Report 184 3 Intermediate Frequencies Table I

Several changes were recorded.

For all entries, the various TV standards involved were now identified by the ITU standard letters, a classification that had been initiated at ST61.

For Japan, only the newer higher IF was shown, as being applicable to all-channel receivers.

Yugoslavia was added to the list of Western European countries. For these, the standards shown were B and G, with no mention of H.

The USSR entry had been expanded to USSR and some OIRT countries. As would be expected, standards D and K were listed.

An entry for African Countries using standard K1 were added, showing the 40.20 MHz VIF, 33.70 MHz SIF combination developed at the ITU Geneva 1963 African Broadcasting Conference. The IF channel limits indicated that it was 8 MHz wide, which contrasts with the 8.5 MHz shown for standard L, perhaps surprising given that in the Geneva 1963 documentation, it was conceded (in a French submission) that standard K1 (or K* as it was then known) nominally required an 8.5 MHz channel, although it was to be used at 8 MHz channel spacing.

The CCIR 1982 Geneva and 1986 Dubrovnik Plenary meetings both resulted in the reissue unchanged of Report 184-3 from Kyoto 1978.

At the CCIR 1990 Dusseldorf Plenary meeting, Report 184-3 was deleted without apparent replacement. One supposes that it was seen as having served its purpose.

CCIR was superseded by, or perhaps effectively became ITU-R. The TV IF list then appeared just once – as far as I can find -in an ITU-R document, namely “Recommendation ITU-R BT.804*,** Characteristics of TV receivers essential for frequency planning with PAL/SECAM/NTSC television systems”, dated 1992. The complete document may be found here: https://www.itu.int/rec/R-REC-BT.804/en. That internet page also shows that it was dated 1992 March and was withdrawn on 2012 January 27.

Annex 1 to BT.804 included section 2, “Intermediate Frequencies for Television Receivers”, from which I have extracted Table 1:

ITU R BT.804 199203 Table I

The format is essentially the same as used for the final CCIR Report 184-3, with which comparison may be made.

References to systems A (405 lines) and E (819 lines) have been deleted.

“Russian Federation” had replaced “USSR and some other OIRT countries”.

For the African Broadcasting Area, system K1, two IF sets have bene added to make three in total. One was 39.90 MHz VIF, 33.4 MHz SIF, shown as an 8 MHz IF channel. The other was 32.70 MHz VIF, 39.20 MHz SIF, but shown as an 8.5 MHz channel. Clearly this was simply the French standard IF for system L. This multiplicity of system K1 IFs is the subject of ongoing discussion in this thread.

The footnote referring to the French system L IF as being SCART Recommendation No. 103 had added to it “In Band I, a double transposition is used.” That creates a confusing situation. As I understand it, when the use of system L in Band I was planned, the use of inverted channels (vision carrier high) was chosen in order that the standard IF channel (VIF low) could be used with supradyne (oscillator high) operation, infradyne operation being precluded for Band I channels. Had this not been the case, then double transposition (double conversion) was one of the ways around the problem. Another would have been to use a “double-ended” IF channel, with Nyquist slopes at each end. But inverting the Band I channels was the simplest solution, at least for system L-only receivers. I’ll leave further discussion on this for a future posting.

What was the “Standard” column in CCIR Report 184-3 became the “System” column in ITU-R BT.804. Evidently there was a change in “official” terminology, that being something that could be discussed in the concurrent “Analogue Television Broadcast Transmission System Letter Designations” thread, https://www.radios-tv.co.uk/community/black-white-tvs/analogue-television-broadcast-transmission-system-letter-designations/. Also to be mentioned therein is ITU-R BT.470, which became the repository for defining information on the various analogue TV systems, following on from the previous CCIR Report series.

Cheers,

Steve

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Topic starter Posted : 25/10/2018 2:02 am
Synchrodyne
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Referring to the preceding post and in particular the last part referring to ITU-R recommendation BT.804, something that I omitted mention of, although I had highlighted it in the pertinent attachment, was the addition of China to the IF list. It was shown as using system D with an HF of 38.00 MHz VIF, 31.50 MHz SIF, that is the same as the then-current Russian IF.

Earlier in the thread, it had been noted that there were some sources that recorded a 37.00 MHz VIF, 30.50 MHz SIF for China. That the latter was actually used seems not to be in doubt, but its status is as yet unknown. It might have been the standard before the 38.00/31.50 MHz IF came into being, or it might have been an ad hoc number chosen by some makers.

Basis a limited search, I haven’t found any evidence that SAWFs were made for 37.0/30.50 MHz, although they were abundant for 38.0/31.50 MHz. One could postulate that perhaps 37.0/30.50 MHz was the “original” IF in China, dating back to the start of TV there in 1957, and at a time when Russian and the OIRT countries were still using 34.25/27.75 MHz. Then when the SAWF age arrived, perhaps there was a rethink or simply capitulation resulting in a change to the newer OIRT IF of 38.0/31.50 MHz.

On the other hand, in 1989-90, well into the SAWF era, Philips was still offering an evidently China-oriented VHF-UHF TV tuner with 37.0/30.5 MHz IF in its latest series, namely the UV411HKM, outline data attached.

Philips DC 03 1990 p.05

Cheers,

Steve

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Topic starter Posted : 25/10/2018 11:47 pm
Synchrodyne
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I was thinking that whilst there were still some items from the preceding posts worthy of further discussion, nonetheless we were reaching something of a stasis in terms of the likelihood of significant further information coming to light. But a look into the “documents” section, as distinct from the “Final Acts” section of the ST61 documents at the ITU site has revealed some more information of importance. Searching those documents is something of a “dumpster diving” exercise, as they are not in subject order, so one cannot always be sure of having found all that is relevant.

A key point is that ST61 was preceded by a special CCIR “Meeting of Experts”, held at Cannes in 1961 February-March, to establish a technical base for ST61 itself. The report from that meeting was adopted at ST61 and included as an annex to document #2-E.

Individual country administration submissions to the Cannes meeting included information as to which 625-line variant (or variants) they were considering for UHF TV services, what receiver IFs would be used, what co-sited transmitter channel combinations were wanted, and what co-sited channel combinations should be avoided. By that time there had been general agreement on the use of 8 MHz channels at UHF throughout the European broadcasting area, as covered in Report #123 from the CCIR 1959 Geneva meeting. Not all countries appeared to have made such submissions at the Cannes meeting, though, with some going direct to ST61, and some amending their Cannes submissions for ST61.

The inclusion of receiver IFs in the deliberations was particularly appropriate for UHF, where with then-feasible IF numbers, oscillator frequencies were inevitably in-band, as were images. Also there was the possibility of IF beats between transmitters with channel spacing proximate to the IFs. In the USA, the FCC had wanted the new “high” IF (45.75 MHz VIF, 41.25 MHz SIF) to be in place before it made its geographical UHF channel assignments, for which a list of so-called “taboos” was developed based on the new standard IF.

As might be expected, most of the Western European countries already using what was later known as system B at VHF were proposing to use what became systems G or H at UHF. In all cases except. Italy, they proposed the use of the existing system B IF, namely 38.9 MHz VIF, 33.4 MHz SIF. Italy was different, to quote from the document:

Italy has special characteristics due to the existence of two intermediate frequencies and receiver oscillator harmonic radiation in Bands I and III has to be considered.

Intermediate frequencies: Picture 38.9 Mc/s and 45.75 Mc/s
                                                 Sound 33.4 Mc/s and 40.25 Mc/s

It would appear that by 1961, there was already some use of the European standard system B IF, as well as the established Italian standard IF.

France was proposing to use what became system L, with an IF of 32.7 MHz VIF, 39.2 MHz SIF. So it had already established its standard for that system.

The Eastern European countries mostly proposed what became system K. In respect of IFs, the Russian submission was:

Intermediate frequencies: Picture 34.25 Mc/s and 38.0 Mc/s
                                                 Sound 27.75 Mc/s and 31.5 Mc/s

Double frequency conversion may be used for reception in Bands IV and V using the carrier frequencies of channels 1, 2 and 3 (Band I) as the first intermediate frequencies.

Thus the 38.0/31.5 MHz combination was already developed, if not in use by early 1961. The double conversion at UHF was an interesting approach, although using working channels as 1st IFs might have been a recipe for problematical interferences.

Poland indicated 38 MHz VIF, 31.5 MHz SIF. Roumania indicated a VIF of 34.5 MHz – fractionally away from the 34.25 MHz norm - but also said that this might be changed if the IBTO adopted standard IFs. Czechoslovakia indicated 34.25 MHz VIF but said that might be changed.

The UK proposed use of what became system I. The IFs were stated to be 39 to 39.5 MHz VIF, 33 to 33.5 MHz SIF.

Unusually, these were stated as ranges rather than single numbers. It was as if the preliminary work had been done, but not the final refinement, which resulted in the 39.5/33.5 MHz combination. Also noteworthy was that the lower end of the VIF range was just fractionally above the system B 38.9 MHz number. Anyway, one could say that the finally chosen combination was “in play” ahead of ST61, and was not developed after it, as I had previously assumed.

Ireland appeared not to have made a submission to CCIR Cannes, but it did to ST61, as part of addendum 18 to document 7-E, wherein it proposed system I with an IF of 39.0 MHz VIF, 33.0 MHz SIF. In the end though it followed the UK choice of 39.5/33.5 MHz.

The Belgian submission to ST61 was addendum 2 to document 7-E. Therein it was proposing that it might use either system G/H or system I. For the former, the standard IF, 38.9/33.4 MHz applied. For the latter, the IF was 38.9 MHz VIF, 32.9 MHz SIF. In the event, Belgium went with system H, but its proposed IF was later used by South Africa for system I.

The above information makes it much easier to interpret this page from the ST61 Technical Annex, which referred to possible UHF interference mechanisms:

ITU ST61 Technical Annex p.57

Previously, one work back from the “i”, “o” and “s” entries what IFs were likely used for the calculations, and also that the K and H (Italy) cases had been worked out on the basis of two different IFs each (now confirmed). But the “d” for double-frequency change had been something of a mystery. Clearly it related to the Russian proposal for double conversion using Band I channels as the 1st IF. Infradyne conversion from a UHF channel to the Russian channels 1 or 3 would put the local oscillator in the (n-7) or (n-10) channel respectively. Infradyne conversion would have been necessary given that supradyne second conversion from Band I channels was unavoidable, and only one channel inversion was allowed in order to arrive at the final IF.

Anyway, to put IF numbers to the ST61 chart, the calculations were made as follows:

System K: VIFs of 34.25 and 38.00 MHz, and double conversion with first conversion cases of both channel 1 and channel 3.

System L: VIF 32.7 MHz.

System H (Italy): VIFs of 38.9 and 45.75 MHz.

System I: VIF in the range 39.0 to 39.5 MHz.

Systems G, H (others): VIF 38.9 MHz.

ITU ST61 Technical Annex p.57 Annotated

 

Cheers,

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Topic starter Posted : 26/10/2018 4:03 am
Pieter H
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Hi Steve,

you triggered me to have a quick search of the Philips tuners for D/K standards. This is the outcome:

  • until 1977 no single D/K specific tuners found. The closest solutions are multi-mode receivers for border countries like Austria and Finland. But these sets were not sold to Eastern block countries, so didn't have to comply with the official IF standards. They used pragmatic solutions, usually to keep the 38,9MHz VIF fixed and use 32,4MHz SIF.
  • In 1977 the U300 UHF tuners claimed to cover standards G/H/K/I, but I haven't seen any formal (D)/K ready Philips sets, so this was probably just an indication the tuner bandpass characteristic was wide enough to pass the 8MHz K-standard signals.
  • In 1983 the regular UV411 and 412 claim again K-coverage, but the IF's are not listed unlike the others, so probably same story.
  • The UV411HKM (where HKM stand for Hong Kong Multi) is the first to cover the China D/K standards, using 37,0 VIF and 30,5 SIF. Seems to have been a unique solution, for the time that China was opening up to western sets.
  • 1988 the UV751/52 tuners, the very first for D/K at 38,0 VIF 31,5 SIF, mainly for China but Eastern Europe would also open up from 1989. Interesting note: the standards in the data sheet are mentioned as D/R (but this can be a typo!).
  • This was continued in the 15 years after with the UV953/54 and UV1355/56.

Hope this helps,

Regards, Pieter

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Posted : 26/10/2018 9:02 pm
Synchrodyne
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According to data on hand, the Philips UV411/412 had 38.9/33.4 MHz IF, but as you suggest, wide enough bandwidth to handle the system D/K bandwidth. The typical Band I bandwidth was 11 MHz.

Philips DC03 1990 p.67
Philips DC03 1990 p.75

The multistandard receivers were certainly interesting as far as IF choices were concerned. As a general rule, one might say that IFs were typically chosen to align with the standards obtaining in the applicable home country, with different cross-border systems then having to fit in with that. So for system B countries that bordered system D countries, dual-standard receivers probably used the standard 38.9/33.4 MHz IF for system B, and 38.9/32.4 MHz for system D. Commonality of VIFs was logical for intercarrier receivers. Although any setmaker choosing the split-sound pathway for higher-quality sound might have opted for a common SIF, and so 39.9/33.4 MHz for system D.

A “problem” area, as it were, was providing coverage for the Band I channels for systems A and E (and when these were gone, for system L’) which, short of double-conversion, required an IF channel of the SIF-high type, whereas the norm, and required for all other system Band I channels, was SIF-low. That was because only supradyne operation was feasible at Band I frequencies. Band III channels for any system were not a problem, as either supradyne or infradyne operation was possible.

In that context, the Philips AT7650/25 tuner mentioned by Pieter H. in an earlier post was an interesting example. It provided full coverage of the French system E channels, both Band I and Band III, using the standard 28.05/39.2 MHz IF. Then it added channel E7 for reception of the Luxembourg system F transmitter with 33.7/39.2 MHz IF, evidently chosen for commonality of sound IFs. The inverted IF channel, as compared with normal system B/C/F practice was available at Band III where infradyne operation was possible. This arrangement suggests that a receiver equipped with this tuner would be home-country France, suitable for use anywhere in France, but particularly in those parts where the Luxembourg transmitter could be received. Given that this tuner dated from 1963, one would expect that it would have been used in a VHF-UHF receiver that also covered system L with 39.2/32.7 MHz IF.

Evidently the Luxembourg channel E7 transmitter coverage in France was big enough to justify this rather specialized approach. I have “borrowed” this map from UKVRR, from an excellent posting by “ORTF & Co” back in 2015 December, see: https://www.vintage-radio.net/forum/showpost.php?p=807416&postcount=304.

Tele Magazine 10 16 01 1960 p26 carte TV etrangeres 2

It shows that the Luxembourg transmitter had a fairly large footprint in France, easily including Metz and possibly providing an acceptable signal as far south as Nancy. So the all-French-channels-plus E7/system F receiver just for this overlap area was reasonably justified.

Apparently the overlap with the British 405-line system in Normandy and Brittany resulted in the use of dual-standard 405/819-line receivers, as noted in Wireless World 1962 October:

WW 196210 p.482 French 819 405 TV Receivers

My best guess is that such receivers would have covered all of the French VHF channels, using the standard 28.05/39.2 MHz IF, with some system A channels using a 35.7/39.2 MHz IF, i.e. with common SIF. The Band I system A channels required an SIF-high IF channel, easily provided in this case.

There were some French 5-system receivers in the pre-UHF days, such as the Telemaster VF5D, mentioned in WW 1959 October:

WW 195910 p.456

That surely was problematical in IF terms. System A coverage would certainly have included Band I, and short of double-conversion, that in turn meant an SIF-high IF channel. Such was also required for the system E Band I channels, sometimes omitted on border area multistandard receivers. But the system B/C/F Band I channels required an SIF-low IF channel. My best guess is that this type of receiver would have used a double-ended IF channel, with a good chance that the SIF-high case was the standard 28.05/39.2 MHz for system E and 35.7/39.2 MHz for system A. Perhaps 38.9/33.4 MHz was used for the SIF-low case, but one could also postulate 32.2/37.7 MHz on the basis that this would have put the lower adjacent sound at 39.2 MHz, the rejector for which – also required in the “other” vision IF channel -would also have served to shape the Nyquist flank over 37.7 MHz.

For the Belgian transmitter overlap area in France, Belgian-style receivers – with limited system E channel coverage, Band III only - would have been possible, as I don’t think that there were any system E Band I transmitters in that area. The same might have applied in respect of the German and Swiss overlap areas, although I think that there was a system E Band I transmitter between those two areas, perhaps with overlapping each a little.

Cheers,

Steve

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Topic starter Posted : 28/10/2018 9:31 am
Synchrodyne
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The system L’ situation in respect of multistandard receivers was well described by Jackson and Townsend, pertinent page attached:

Jackson & Townsend p.51 3

One may find “hard” evidence that the dual-purpose or double-ended IF strip was used in practice.

Firstly, double-Nyquist SAWFs were available, apparently as standard items. Some VIF pairs that were used for these were 33.4 and 38.9 MHz, and 33.9 and 38.9 MHz, per the attached examples.

Siemens G3957M p.182
Epcos K3953M p.02

Thus the VIF for system L’ would have been 33.4 or 33.9 MHz, with SIF at 39.9 or 40.4 MHz.

The VIF for system L (and others) would have been 38.9 MHz, with SIF at 32.4 MHz.

Secondly, there were “multistandard” tuners, such as the Philips UV815/816, which provided 33.4 MHz VIF for system L’ and 38.9 MHz VIF for system L (and others).

Philips DC 03 1990 p.217

Whether double-conversion for system L’ was used in practice I do not know. More generally, from the ST61 proceedings, it is apparent that the Russians at least contemplated double-conversion for the UHF channels, using a Band I channel as the 1st IF. In the USA in the 1990s, Mitsubishi advertised its TV receivers (and VCRs, I think) as having double-conversion tuners. I don’t have any details, but I have a vague recollection that initial upconversion, to somewhere above the top end of the UHF band, was used.

Cheers,

Steve

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Topic starter Posted : 28/10/2018 9:41 am
Nuvistor
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I have heard of the Nyquist frequency in analogue to digital circuits but not a Nyquist slope filter.

After some online searching from what I read it is a vestigial sideband filter for use in TV circuits. Surprisingly in the C&G courses I took it was never referenced as a Nyquist slope filter.

Its possible that it was always known by its inventor name but the courses I took just decided not to use it and just use the VSB. A VSB filter could of course take many forms so I can accept that giving it a name to differentiate a TV IF filter from other shapes is useful.

Hope my understanding is correct, as usual corrections gratefully accepted.

 

 

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Posted : 28/10/2018 10:29 am
Pieter H
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Hi Steve,

you mention many different things, so let me try to comment on a few of them:

  • I think your analysis of the different solutions for L' are correct. And indeed later, when SAW IF filters were common, the two-sided Nyquist slope filters became the default solution for multi-sets.
  • I think the coverage map of Luxembourg E7 is conservative. From what I've read on French forums it covered almost the entire Northern France. Also the transmit power was steadily increased to maximize the covered area. Apparently to the frustration of French authorities and probably also French set makers, since they were more or lest forced to always support the Luxembourg standard, because this channel was and still is pretty popular in France.
  • I haven't encountered a single Philips French-UK multi in all my analyses so far, i.e for VHF. This doesn't mean there wasn't an exotic set maker offering it, although the potential market will have been small. To investigate whether such multi-sets really existed it might be interesting to find out what type of TV sets were used on the British channel islands. When the UK went UHF it all became much more straightforward, and with global chassis they were both covered.
  • The same for dual-conversion tuners, either D/K or other standards. This will be a topic in one of my upcoming new pages, but dual-conversion is in essence very bad for off-air reception. So the only places where it really is used is US cable TV, which indeed used GaAs-based up-conversion to 1 or 1,2GHz. At the expense of a lot of power consumption. The other area is satellite reception, but there the received signal dynamic range is much lower, making it feasible. And of course the high RF of 10-11GHz required an intermediate step, so this is dual down-conversion, not up-down. In the end all terrestrial tuners I know of used the classical single-conversion to the well-known IF's. This would only change fundamentally with the introduction of the Philips integrated IC tuner, which will be the last part of my story.

Frank,

As to the wording: you are fully right that the most accurate description of the TV slope around the picture carrier is Vestigial Sideband Modulation slope or VSB-slope. However, the brilliant Mr Nyquist did more than his sampling theorem and defining the Nyquist bandwidth. These slopes are indeed also commonly referred to as Nyquist slopes. So effectively two different but correct names for the same phenomenon.

Cheers, Pieter

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Posted : 28/10/2018 2:08 pm
Synchrodyne
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Hi Pieter:

Agreed that there are several subtopics within the main topic here.

Regarding the putative French 405/819-line dual-standard receiver case, the WW 1962 October article said that there were understood to be about 2000 such receivers in operation along the coast of the Havre peninsular. That small number seems to be something that one or two smaller receiver makers might have offered as a specialist item, but probably not a market that would have been attractive to the major producers. Possibly Télémaster addressed it. Insofar as it evidently had available a multistandard 405/625/819-line model in 1959, then it also had the basis for a somewhat simpler 405/819 model for the Havre peninsular. Also, or alternatively, it might have sold its V5D as such into that market. I can’t find much information on Télémaster, but it does seem to have been a smaller outfit, or perhaps a small TV and radio section of a larger combine. The WW 1959 article also mentioned setmaker Clarville as offering a “decodeur bilingue” for the dual-language North African broadcasts. Clarville may have been another smaller specialty manufacturer who was inclined to cater for niche markets.

From the UK side, I think it unlikely that any of the setmakers would have offered 405/819 dual-standard receivers for the Channel Islands market, but we might be surprised. On the other hand, such receivers from French makers might have been sold there. The WW article mentioned that the Channel Islands ITV station advertising included some from French manufacturers. That could have included French TV receivers. What is known is that the local “cable” company, Rediffusion did include French TV in its service, per the attached:

Rediffusion Jersey p.10

As far as I know, Rediffusion Jersey had an HF (not VHF) distribution system. Whether it distributed the French 819-line system as received, consequently with dual-standard receiving units, or whether it undertook head-end (optical) conversion is unknown. I should have thought that standards conversion outside of the broadcast environment back in those days (1950s into the 1960s) was too complex and too demanding of engineering time, but the fact that it was used in shipboard applications of that era suggests otherwise:

WW 196101 p.12 TV Afloat

 

There seems to have been a history of dual standard TV receivers in France. Early on, at least according to this WW 1951 November article, there were some 441/819-line receivers:

WW 195111 p.459 French Dual Standard TV

Then the “Strasbourg” was an early border area 625/819-line receiver:

WW 195407 p.324 Strasbourg TV Receiver
WW 195406 p.263 Strasbourg TV Receiver

 

Cheers,

Steve

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Topic starter Posted : 04/11/2018 2:37 am
Synchrodyne
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Having looked through the ITU ST61 documents, which revealed quite a bit of information on TV receiver IFs, I did the same for ITU ST52, which was the first European VHF planning meetings. The ST52 documents are available here: https://www.itu.int/en/history/Pages/RadioConferencesRegional.aspx?conf=4.81.

Here I found comparatively little on receiver IFs, in fact just one small section as follows:

>>>>>>>>>>>>

Intermediate frequency of a TV receiver

A number of Delegates were in favour of an IF band close to the lowest TV channel, apart from a necessary frequency spacing, viz, somewhere between 30 - 40 Mc/s. In Italy, the band 40-47 Mc/s has been reserved for this purpose; in that country, the lowest TV channel being 61-68 Mc/s.

The Swedish Delegate expressed a preference for a lower intermediate frequency (below 20 Mc/s), as the mobile services are situated between 30 and 40 Mc/s.

ITU ST52 Doc 42 E p.07 TV IF

>>>>>>>>>>>>

Generally this accords with what has already been found from other sources. The Italians were known to have been quite early in declaring a protected national TV IF “channel”, and this was evidently done at the same time as the original national channel frequency assignments were made, information on those being presented elsewhere in the ST52 documents.

In the British case, a standard IF was not declared until late in 1954, the main motivation for it being the planned start of Band III transmissions in 1955. In the Western European case, what became the standard IF was declared as the optimum some time in 1954, although it had seen some previous use. The exact date for the French standard IF is unknown, but estimated as being 1955. However, as previously discussed, it was a more-or-less inevitable outcome of the tête-bêche channelling system, details of which were presented at ST52, albeit with a different numbering system to that which was finally adopted.

I cannot find mention of the earlier Russian 34.25/27.75 MHz IF in the ST52 documents. Absence of evidence is not evidence of absence, but the Russians provided a significant input to ST52, including much on TV channel frequency and geographical assignments. They proposed extending Band III down to 144 MHz to accommodate extra channels (which did not happen), and going into ST52, they had not proposed the use of Band II (87.5 to 100 MHz) for TV purposes, nor the 76 to 87.5 MHz space immediately below Band II. Had their extensive proposals included a TV IF channel, then it is reasonable to expect that it would have been mentioned in the ST52 documents.

So at least as a working notion, until hard evidence comes to light either way, I’d say that the Russian 34.25/27.75 MHz TV IF was developed after ST52, and after it was decided to use the 76 to 100 MHz band to accommodate three 8 MHz TV channels. That puts it into approximately the same development timeframe as the other European standard TV IFs.

The British and Western European standard TV IF channels were in the generally preferred 30 to 40 MHz range, i.e. as close to the bottom edge of Band I as was reasonably possible. The French standard TV IF channel inevitably reached down below 30 MHz because it was 14 MHz wide. That the Russian standard TV IF channel in part dropped below 30 MHz may have been because that was the optimum position for it taking account of the Band I and Band II channels, and those in between.

ST52 included a final protocol, that listed just two out-of-band assignments, namely the Italian 81 to 88 MHz channel (later channel C) that slightly overlapped the lower end of Band II, and a 216 to 223 MHz TV channel (later channel E11) for use in Belgium, West Germany and Switzerland.

The Band I list included Russian and Eastern European stations in the 56.5 to 58 MHz and 66 to 78 MHz ranges, the former being the gap between what became TV channels O2 and O3, and the latter the gap between the upper edge of what became channel O3 and the top edge of Band I. No out-of-band FM stations in the 68 to 73 MHz range were listed, nor any TV stations in the 76 to 87.5 MHz range, or within Band II.

In fact the Eastern European out-of-band FM and TV stations did not appear in an ITU list until the output of a 1960 Geneva special conference, the documents for which are available here: https://www.itu.int/en/history/Pages/RadioConferencesRegional.aspx?conf=4.86.

The ST52 documents also show that the development of the channel numbering systems for the various European VHF TV channels was not a straightforward process; for most sets, it did not go direct from “zero to final”. That forms material for a possible subsequent posting, perhaps as a follow-on to the analogue-television-broadcast-transmission-system-letter-designations series ( https://www.radios-tv.co.uk/community/black-white-tvs/analogue-television-broadcast-transmission-system-letter-designations/#post-93844aps).

Cheers,

Steve

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Topic starter Posted : 06/11/2018 4:02 am
Terry
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In the UK, before 34.65/38.15MHz was adopted, there was what I've always considered to be an earlier standard: 16/19.5MHz.

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Posted : 06/11/2018 6:16 pm
Pieter H
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Terry,

for details on that see my earlier post of September 29 in this thread (page4).

It shows the transition from the different lower IF's to the final BREMA standard over time and per manufacturer.

Cheers, Pieter

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Posted : 06/11/2018 7:40 pm
Terry
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Thank you for pointing me to that earlier post. I've been busy on other things recently and have obviously overlooked some posts.

Obviously it was not as common as my memory lead me to believe!

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Posted : 06/11/2018 8:03 pm
Synchrodyne
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As mentioned in my September 28 post, I had previously been inclined to think of 16.0/19.5 MHz as a general proxy for UK TV IF practice in the Band I-only days, and saw it as the modal choice (although not supported by any rigorous analysis) and as such perhaps a de facto but not a de jure standard.

The pathway to UK standardization is illustrated at least in outline by a couple of Wireless World (WW) items. The first is an editorial from the 1952 February issue, calling for the development of a standard IF, and stating that at the time of writing, nonesuch existed:

WW 195202 p.41 UK TV IF

The second was a rejoinder from BREMA in the 1952 April issue, indicating that the subject had been a BREMA study subject since 1949, and was at that writing under renewed study. In particular there was a debate about the relative merits of “low” and “high” IFs.

WW 195204 p.145 UK TV IF

The final outcome was that a decision was made in favour of the “high” IF, 34.65/38.15 MHz, a summary of the reasons for which was published in WW 1954 December, and included as an attachment in my September 28 posting.

Nonetheless the early “non-standard” IFs certainly should be recorded. Some information in respect of the European situation was provided in a WW 1954 July summary of an EBU enquiry into TV receiver IFs, published as document Tech. 3062-E. Unfortunately this does not appear to be available at the EBU website. I think that I posted the WW article very early in this thread, but here it is again in better quality.

WW 195407 p.322
WW 195407 p.323
WW 195407 p.324
WW 195407 p.325

 

Cheers,

Steve P.

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Topic starter Posted : 07/11/2018 4:45 am
Pieter H
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Hi Steve,

Good stuff!

Most surprising in the table on the 2nd page above is the fact that both Switzerland and Denmark were at the time contemplating to use other IF values than what I thought was a fairly broad continental standardization to 38,9/33,4MHz. I don't think these ideas have lived for long, since as far as I know they were never implemented. I've never seen a Philips tuner or TV with these IF values for these countries, so I assume that is the same for other TV brands.

Your new data re-confirms that IF "standardization" was a pretty pragmatic and mildly chaotic development.

Cheers, Pieter

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Posted : 12/11/2018 11:16 pm
Synchrodyne
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Thanks Pieter:

I suspect that different groups may have arrived at slightly different initial conclusions as to the best choice for a “high” IF for the CCIR TV system (i.e. what was later system B.) I suppose that they might have applied different weightings to each of the interference possibilities. Also, over time, the numbers might have been refined somewhat. The EBU data was gathered during 1953 and the early part of 1954, so some submissions may have been early in this period and some later on.

The 38.9/33.4 MHz IF might have been originated by Philips. Fewings & Fife, in their 1955 paper on multichannel TV tuners, included the following in the bibliography, which one would deduce as having been their basis for quoting 38.9/33.4 MHz as the standard IF for the CCIR system:

“W. Holm and W. Werner, “Choice of an intermediate frequency to suit the C.C.I.R. standard,” Funk und Ton, 8, pp.129-138, 1954.

Werner was a Philips Netherlands staffer and co-author (with Kerkhof) of the book “Television”. Holm wrote the book “How Television Works” in the Philips Technical Library series, although I don’t know whether he was a Philips staffer. I think he was from Germany. Funk und Ton, as best I can determine, was – maybe still is – a German journal covering radio, TV and audio matters, I suspect more of a professional than a trade or mass-market publication.

The Werner & Holm article in Funk & Ton might have been the catalyst for TV IF standardization throughout the European system B area, except in Italy, with the outliers deciding that it was best to fall in with the 38.9/33.4 MHz IF proposed therein, and evidently already chosen for the Netherlands and Germany. It could be that W&H had provided a more thoroughgoing analysis than had previously been seen, and possibly they also gave reasons why some of the other numbers shown in the EBU report, such as 39.5 and 39.75 MHz VIF, were less satisfactory. Thus far I have not been able to find that Funk und Ton article, and I’d say the probability of my so doing is quite low.

Given that 38.9/33.4 MHz was a German choice, I’d expect to find that it was covered by a DIN standard, but so far I have not seen any evidence that it was.

Cheers,

Steve

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Topic starter Posted : 15/11/2018 2:03 am
Till Eulenspiegel
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Stella 405 line TV receivers ST8617U and ST8621U (1957).

Alignment notes taken from the 1958/59 Radio and Television servicing book.

Sound IF Although the actual sound IF is 38.15Mc/s, the two IF transformer are tuned to 38.35Mc/s. This "off-setting" allows for an alternative adjustment to the oscillator frequency under difficult reception conditions. By so doing, the vision carrier moves nearer to the top of the response curve, thus improving the vision gain and improving the signal-to-noise ratio. Furthermore, the sound IF moves and peaks at 38.35Mc/s.  De-tuning the sound carrier up 200Kc/s will not materially effect the sound gain, the overall sound bandwidth at 6 db down being 900Kc/s.

The Stella ST8617U was electrically identical  to the Philips 1786U.  There is no mention about the off-set sound IF in the servicing notes for the Philips receivers.

Till Eulenspiegel.

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Posted : 28/11/2018 10:07 pm
Nuvistor
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That’s an interesting idea, was the fine tuner preset on the Stella TV so that it could be set for best operating point on installation?

Otherwise I believe the customer would just tune for loudest sound.

 

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Posted : 29/11/2018 8:50 am
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