View Full Version : Television transmission types.

Loose rivets
4th Aug 2010, 05:25
This might come in handy.

I'm astonished there are so many PAL transmissions.

Can I Use My TV In Another Country? (http://ars.samsung.com/customer/usa/jsp/faqs/faqs_view_us.jsp?SITE_ID=1&PG_ID=0&AT_ID=247203&PROD_SUB_ID=0&PROD_ID=41&EMAIL_ID=)

From FAQ can I use my tv in another country?

Support for PN50C7000 50" Class (50.1 inch diagonal) 1080p 3D Plasma HDTV- NEW SAMSUNG (http://www.samsung.com/us/support/detail/supportPrdDetail.do?menu=SP01&prd_mdl_name=PN50C7000YF)

4th Aug 2010, 06:46
You can add the biggest viewing population, China, to your PAL list.

4th Aug 2010, 07:25
I suspect that the list on the first URL you've quoted is out of date. For a start it refers to 'Czechoslovakia' which hasn't existed for about 20 years, and under the SECAM list mentions countries (including Croatia, Greece, Liechtenstein, Hungary) which do not use SECAM.

SECAM was a standard created by French TV manufacturers to protect their own industry, primarily state owned Thomson, and was exported from France to countries under French influence. It was also used in some East European/Iron Curtain countries, notably the German 'Democratic' Republic to prevent the inhabitants of those countries from watching the evil capitalist propaganda programmes from the West and wanting to escape across the border.

NTSC - which stands for Never The Same Colour - is used principally by the USA and countries under its influence.

There are various PAL subsystems (I/B/G etc) the principal difference being the carrier separation between the audio and the video channels (around 6 Mhz I think)

4th Aug 2010, 09:28
SECAM - Scientifically engineered contraire American methode


tony draper
4th Aug 2010, 10:34
These differing transmission systems cause no end of trouble,one knows this because one had to fly all the way to San Fransisco once join a cruise ship and modify 200 tellys so they could switch betwixt em as the ship tootled round coasts with Secam Pal and NTSC systems,I mean we invented television why didn't we insist they all use PAL.

4th Aug 2010, 14:42
An interesting bit of TV history, referring to the choice of systems and much more:

The Men Behind The Masts - ITA /IBA - Independent Broadcasting Authority (http://www.mds975.co.uk/Content/iba_behind_the_masts.html)

Loose rivets
4th Aug 2010, 17:40
Yes, I didn't really look at the lists. China? That ups the anti.

I guess I was too busy rejecting the latest telly...a 52" Sony Bravia. It is now 5th on the list of rejects, and way up there on "who the f:mad:k designed that software." Takes soooooo long to pick Favorites from the most arty-farty but useless menuing system in the world. What's more, the picture is so bad it's a non-starter and the Bravia 3rd generation processing...? Well, I'm done venting.

I recall being quite impressed with Secam. 800 lines plus, wasn't it? Strangely, Sony managed to screw a good picture out of NTSC when they invented their Trinitron. No connection, but just at the same time as the tube technology.

PAL was a miracle - packing all that colour coding into such a small bandwidth, then changing phases to send an average colour to the brain. Really very impressive British old-style engineering.

I belong to a forum that deals with vintage kit. Many of the guys downgrade their signal and pump it into a restored old telly. Some even redesign their entire rooms to be in the period. One picture makes me want to go back to the late 50s, it looks so homely.

4th Aug 2010, 18:12
Eh ? Analogue ? I thought most countries used the same digital television (DTV) standard these days.

PAL, SECAM etc are surely a thing of the past...

Spain turned off the last analogue transmitters earlier this year. I know my little pocket DTV works in Spain and in France and in the UK, so all ARE using the same digital standard for television transmission.....

Loose rivets
4th Aug 2010, 18:38
I wish the Americans would join the club. If we had to ship our stuff home, the telly would be a hi-value item we'd have to sell for next to nowt. The 60Hz and (multiples of) frame speeds are also an issue.

Anyone know why Plasma is stated to have a 600 hz frame refresh speed? If correct, where does the data come from? Just made up, I suppose.

4th Aug 2010, 19:19
Of the three major colour standards SECAM is the most robust with respect to degradation by imperfections in the transmission system. It will withstand 40 degrees of differential phase and 20 percent differential gain and still render an excellent colour picture. It was very suitable for installation in countries that could not afford to upgrade their transmission or microwave facilities. It was also a better VTR standard, requiring much less technical elaboration to play back a signal. I am told that as late as 1964 ABC considered it for a VTR standard. Home videotape recorders used the same principles as SECAM.

It is worthless as a production standard as the signal mist be decomposed before being manipulated with standard production methods (Fade key etc). It is also, as I know from experience, highly engineer resistant. A good SECAM signal and a bad one look very much the same on a 'scope.

Later SECAM systems produced in PAL and converted to SECAM (Easy) for transmission. Rather difficult though to convert back to PAL if you want to manipulate the signal.

L.R. Yes, done by interpolation.

tony draper
4th Aug 2010, 19:35
Wont pure digital transmission eventually do away with these standards? been out of the loop for a long time so haven't a clue how digital stuff is sent.

4th Aug 2010, 19:57
Well, it's not exactly pure as somewhere it's modulated onto a carrier. Europe still uses the CCIR (625) line standard for the recovered signal as far as I know and North America uses the EIA (525) line system for standard definition.

Further to Loose rivets' question: In the North American system (ATSC) about 95% of the information is lost in the digital compression process and re-created in the TV set. That's before the interpolation to a higher refresh rate!

I don't imagine Europe (DVB) is much better.

tony draper
4th Aug 2010, 20:06
In HD TV say 1080p are different HD camera used in the studio? ie is HD right from the output of the Camera? or is HD just a matter of increasing the resolution of the standard pictures transmitted?

Hagbard the Amateur
4th Aug 2010, 20:21
1080 pickup is exactly what it says on the box in terms of modern 3CCD cameras. In post production, it is possible to compress to any format required. Still 1080 tends to test lighting gaffers, make up artists and, of course, actors because every wrinkle is super visible. True HD is scary stuff if you are in front of the lens. For my humble documentary films, I'm still sticking with 720 for the sake of my subjects.

4th Aug 2010, 20:52
720p if it is maintained from one end of the system to the other has much better temporal resolution then 1080i. Better for most sports in other words.

Looking on my standard def TV set it looks to me as if down conversion from natively HD formats tends to emphasize skin defects. End to end aspect ratio control is p*** poor as well.

Windy Militant
4th Aug 2010, 22:46
Don't know about the wiggly amps side, but I once did a mast climbing course with some BBC Transmission types. Apparently the Lovies used to totally ignore them and refused to acknowledge their existence, but as the man said without the Transmission types they'd just be a bunch of Am Drammers as nobody would ever see anything they did! :}

Loose rivets
5th Aug 2010, 06:06
but I once did a mast climbing course with some BBC Transmission types.

Well, of all the things in the world that I wouldn't have guessed you'd have to do, it would be a mast climbing course. What would Fred Dibnah have said?

Only thing I recall about masts is that the one near us - Essex/Suffolk, was tapered down to nowt, and stood on a 4" ball bearing. I wonder how they greased the ball.

Ancient Observer
5th Aug 2010, 11:50
How did you resist the temptation to take it apart?

tony draper
5th Aug 2010, 12:08
Installed some CCTV cameras on a repeater mast in Yorkshire,can't remember the name of the place now,they were to keep toot on the other CCTV cameras that the locals were hopping over the fence and nicking,high enough up so clambering up to steal em would cause pause for thought.

5th Aug 2010, 15:08
I thought most countries used the same digital television (DTV) standard these days. :hmm::hmm: PAL/NTSC/SECAM redux.....

Wikipedia: (http://en.wikipedia.org/wiki/Broadcast_television_systems#Digital_television_systems).... Digital television systems
The situation with worldwide digital television is much simpler by comparison.....

The two principal digital broadcasting systems are ATSC, developed by the Advanced Television Systems Committee and adopted as a standard in the United States and Canada, and DVB-T, the Digital Video Broadcast Terrestrial system used in most of the rest of the world.

DVB-T was designed for format compatibility with existing direct broadcast satellite services in Europe (which use the DVB-S standard, and also sees some use in direct-to-home satellite dish providers in North America), and there is also a DVB-C version for cable television. While the ATSC standard also includes support for satellite and cable television systems, operators of those systems have chosen other technologies (principally DVB-S or proprietary systems for satellite and 256QAM replacing VSB for cable).

Japan uses a third system, closely related to DVB-T, called ISDB-T, which is compatible with Brazil's SBTVD. The People's Republic of China has developed a fourth system, named DMB-T/H......

tony draper
5th Aug 2010, 16:09
When they eventually switch off the analogue signal will digital reception improve? mine is fine but I have heard a few complaints.

5th Aug 2010, 16:39
Swings and roundabouts, Tony. WHEN it's working the signal is as good as the old analogue signal. Can't say "better" as it was always good at my location, on a mountainside 600' asl.

BUT digital seems to need a stronger signal (power, quality) or it pixilates. Main thing is the digital set top box tiny, efficient, and the ones sold here contain a digital recorder that puts the program onto an SD card. All for 39 (wot I paid).

tony draper
5th Aug 2010, 16:51
I live in a good signal area mesef,I can see Pontop Pike from me back door,but I spent part of my life sticking aerials up and I know there are still areas round here where the analog signal is just not to be had off air.

5th Aug 2010, 19:00
I live in a hole. Until Victorian times is was known as 'The Hole' but they renamed it after the orchards that were located at Hole Farm.

A couple of miles to the north we have an analogue radio transmitter and reception of medium wave (and long wave) programmes is excellent.

Digital transmissions come from 20 miles south over several hills that effectively blocks the signal.

tony draper
5th Aug 2010, 20:16
Most of my town was wired up with the Rediffusion RCS system I know this because I helped wire it,we called cable television wired tv in the olden days, this was well subscribed because as I said lots of bumps and lumps in the landscape made off air reception grim in some areas,even when they brough out the repeaters like Fenham and Bilsdale places like Felling were still buggad.