Early French `HD' Television.

[Combwork]

Hi,

I'm needing as much information as possible about an early 1950's French `HD' television. A friend of mine who respects my ability to ferret out information (poor fool) has offered me £50 if I can get enough information, `History of' etc to help him sell it. I'd be happy to split this 50/50 with AudioKarma if I can get enough information for him to cough up. I'm copying his email below. Bit of a challenge this. The French tended then (and now) to go their own way; if there was any easily accessible information available here in the U.K., my friend would have found it................ Jim.

With you unusual ability to ferret out unusual facts about television technology I wonder if you can find any information regarding the French 819 line TV service which they introduced briefly circa 1950 and abandoned shortly afterwards - presumably 'a bridge too far' in favour of a lower standard.

I attach pictures of an 819 line TV.

If you can give me some useful further information I can use to sell this TV I would pay you £50 for the research.

[OvenMaster]

http://www.answers.com/topic/analog-...vision-systems
French 755i

When Europe resumed TV transmissions after WWII, i.e. in the late-1940s and early-1950s, different countries used different resolutions. The UK used 405 lines, most other countries 625 lines (both numbers include the vertical gap, the actual resolutions were lower), but France decided in 1948 to go for 819 lines. The French TV system thus became the world's first HDTV system, and, by today's standards, the French system could be called 755i (not all lines could be used for the actual image — some lines were lost during the vertical retrace). The French 819-line (or 755i) HDTV system was introduced in the 1950s. When, in the late-1960s, a second TV channel and color TV were introduced in Europe, the UK dropped its 405-line TV system (The last 405 line broadcasts were in 1985.) and France dropped its 819-line system (again, with final transmissions from Paris in 1985), making all European countries agree to use 625 lines (576i) for their TV transmissions.

The French "755i" 819-line HDTV system was used in only France, Belgium and Monaco, and in France only for the first French TV channel. It was discontinued in 1986. It was used only for black-and-white TV; color TV in 819-line SECAM never went beyond the experimental stage. It was transmitted only on VHF channels, and a French 819-line TV channel occupied 14 MHz of bandwidth. The system was therefore not PAL, SECAM or CCIR 601-derived.

Ka-ching! Someone is now £50 richer.

Tom

[Combwork]

Originally Posted by OvenMaster

http://www.answers.com/topic/analog-...vision-systems
[i]French 755i ........................Ka-ching! Someone is now £50 richer.

Tom

Thanks Tom,

I've passed this on, along with as much information I could garner including the fact that as well as making WOBULATORS, in 1967 Ribet Desjardins made the WOBULOSCOPE. Whether this is French for osciloscope is anyone's guess, but wobulator sounds like something from a 1950's B movie, as in "Give me the money, or Igor will feed you to the WOBULATOR"
Jim.

[OvenMaster]

Jim, here's a tip to help you practically guarantee that £50 in your pocket. Just put "819 line French television system" in Google and you'll get over 100,000 responses... many of them actually useful!
As for a Wobulator, that seems to have quite a few different meanings other than oscilloscope, among them a guitar pedal effect. I like the B-movie idea best, though.
Good luck collecting the money!
Tom

[rulerboyz]

I'm fluent in French, so I could read or translate any info I find written in French on the subject.

SECAM 755i (1948): Primo sistema HDTV al mondo a 819 linee
,francese.Chiamato “Sècam 755i “(poiché non tutte le linee erano
impiegate per rappresentare l’immagine),era usato solo in Francia e a
Monaco.

I appears as though this was also used in Monaco as well as France. So this television was notable as being the first HDTV system in the world, using 819 lines, although not all of the lines were used to translate the image onto the screen.

8 Novembre 1935 : émission à la définition de 180 lignes et un émetteur d'ondes courtes est installé au sommet de la tour Eiffel.
4 janvier 1937 : premières émissions tous les soirs de 20 heures à 20 h 30. Il y a une centaine de postes chez les particuliers.
3 septembre 1940 : la télévision française est prise en main par les Allemands.
Le 7 mai 1943 vers 15h, la première émission de Fernsehsender Paris est émise depuis la rue Cognac-Jay (ancienne pension de famille). Une autre studio sera aménagé rue de l'Université dans l'ancien « Magic City ». Ces émissions régulières dureront jusqu'au 12 août 1944. Les émissions étaient reçues par un millier de récepteurs en 441 lignes, notamment installés dans les hopitaux et les foyers pour soldats.
1944 : René Barthélemy met au point la définition de la télévision à 819 lignes. Pendant les années d'occupation, Barthélemy a atteint 1015 et même 1042 lignes.
1er octobre 1944 Reprise des émissions de télévision après la libération de Paris. Les émissions sont diffusées depuis les studios de Cognacq-Jay.
1945 : après réparations suite aux sabotages opérés par les Allemands, les émissions de télévision reprennent via l'émetteur de la Tour Eiffel.
5 juin 1947 : premier direct en dehors des studios depuis le théâtre des Champs-Élysées à Paris.
20 novembre 1948 : le standard d'émission est adopté par le décret Mitterrand à 819 lignes , les émissions commencent fin 1949 dans cette définition. La France est le seul pays à l'adopter (les autres pays choisiront les 625 lignes).
9 juillet 1952 : mise en service du convertisseur qui permet aux récepteurs 441 lignes de recevoir les émissions extérieures et reportages en direct comme sur 819 lignes.


1967 : le Secam, une norme de codage de la vidéo en couleurs sur 625 lignes inventé par Henri de France, est adopté pour la télédiffusion française.

It was René Barthélemy who set the standard of 819 lines of resolution in 1944. During the years of German occupation he reached as much as 1015 or 1042. On November 20th, 1948 the French Minister of Information set le standard at 819 lines. The previous 441 line standard was planned to continue to be broadcasted until 1958. Transmission started in late 1949 in that fomat. All the other European countries adopted 625 lines as their standard. In 1952 a converter was made available for sets in 441 lines could receive 819 programming.

France officially adopted the 625 standard in 1967.

The following book would probably be of some interest on this subject (unfortunately you would have to spend all your prize money in order to get it):

http://www.pug.fr/titre.asp?Num=201

[Sandy G]

Wonder when Ze French got color ? Was it on 819, too?...Seems like I remember reading the sound on 819 was AM, as well. Wonder why "819" ? Why not 850, 825, or hell, even 919? Would like to have seen an 819 transmission..

[Combwork]

[QUOTE=Sandy G]Wonder when Ze French got color ? Was it on 819, too?...Seems like I remember reading the sound on 819 was AM, as well. Wonder why "819" ? Why not 850, 825, or hell, even 919? Would like to have seen an 819 transmission..[/QUOTE]

Hi sandy,

Diging into the information Tom sent me, it seems that the French did some early experimental work with colour on 819 lines, but like the UK their public colour broadcasts were on 625 lines (though they used SECAM rather than PAL). Why 819? I don't know. Maybe the AC line frequency in France had something to do with it? Jim.

[rulerboyz]

From what I read I appears as though the first experimental French station to broadcast in color was on March 16, 1963. on canal 22 at 100 kW.

http://www.telesatellite.com/article.../index.asp?p=4

[tubesrule]

The number of lines in a standard needs to be mutliples of small integer numbers. This was required by early sync generators since small integer dividers were the easiest to create using blocking oscilators. This web site has lots of technical information on many different video and RF standards, and shows the integer dividers for most standards.

http://www.pembers.freeserve.co.uk/W...Standards.html

[dtuomi]

The choice of number of lines has to do with frequency divider circuits. Before the advent of IC's you could only do odd numbers (usually primes like 3,5, & 7) of divisions of a main clock frequency to obtain the line and field rates.

So lets take B&W 525 lines at 60hz. The vertical frequency is 60hz. The clock division would be 3 × 5 × 5 × 7 to get 525 lines. And if you multiply by 60 and then divide by 2 you get the horizontal frequency of 15,750hz. When NTSC color was introduced the vertical frequency was reduced to 59.94Hz and the horizontal frequency to ~15,734Hz, but the math still works.

So at 50hz the values of 5 * 5 * 5 * 5 give us 625 line video and the values of 13 x 7 x 3 x 3 give 819 lines.

The number of lines in a TV signal can't be any old arbitrary number. But it does work for a large number of television lines, including hi-def. The Japanese analog standard for hi-def is 1125 lines (1080 active, sound familiar?) at 60hz and its division is 5 x 5 x 5 x 3 x 3.

David

[dtuomi]

Originally Posted by tubesrule

The number of lines in a standard needs to be mutliples of small integer numbers. This was required by early sync generators since small integer dividers were the easiest to create using blocking oscilators. This web site has lots of technical information on many different video and RF standards, and shows the integer dividers for most standards.

http://www.pembers.freeserve.co.uk/W...Standards.html

I'm not sure why I bother, by the time I researched my little dissertation on the subject a perfectly good link was already posted.

David

[Phil Nelson]

Originally Posted by Combwork

well as making WOBULATORS, in 1967 Ribet Desjardins made the WOBULOSCOPE.

I own a 1943 "oscillograph wobbulator," basically a scope with built-in wobbulator:

http://antiqueradio.org/trium01.htm

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

[Combwork]

Hi. $50 as promised just sent to AK. Sorry it took so long............. Jim.

[OvenMaster]

Hah! Nice going, sir!!

[wa2ise]

I was looking to see if any of the digital TV standards might be able to drive this 755i set. It would accept the luma output only (luma=B&W). Unfortunately, nothing really comes close. There's 720p, but the horizontal scan rate is about twice as high as 755i would call for. 1080i is about 2/3 too high. Looks like you would have to build a buffer to convert 720p to 720i, which should make it close enough to 755i for the set to sync up. The buffer would just drop alternate lines of video and also have to buffer the kept lines to play out half as fast as before. That's not really trivial to do. If there are programmable digital TV decoder chips that can be made to create oddball output scan rates, then that would be better. Again, not trivial.