Video není dostupné.
Omlouváme se.
"HOW TELEVISION WORKS" 1952 Educational overview
Vložit
- čas přidán 13. 08. 2024
- "How Television Works" 1952, is an educational overview, restored for discussion and comment. It provides a fascinating look at how television works from the camera tube to the picture tube. It provides a fascinating very basic description back when Television was a very new thing to most people. The television seen in the film is the Bush 9" table top television receiver, manufactured by Bush Radio Ltd. It appears to be a model TV22 or the earlier TV12 (1948). Topics in the film include TV vacuum tube electronics, broadcast, antennas, iconoscope, CRT picture tube, early television transmission, amplifiers, electron gun, TV signal transmission, etc. Shows a British couple watching a very early TV in their home, plus illustrations of how the camera and electron gun work. Very easy to follow. Good quality film!
2k and 4k stock footage available from
www.periscopefilm.com
Original Bush model TV-12 television (1948) was a landmark television introduced in 1948 and had a 9 inch screen, with a Bakelite case. The model TV22 looked nearly identical.
About the Bush TV22 model: (from the Science Museum Group, UK) -
"A Bush TV22 9" table top television receiver, manufactured by Bush Radio Ltd about 1952. Fitted after manufacture with a Band III convertor.
Featuring a 9 inch screen the Bush TV22 was first made in 1950. It remained in production (with circuit improvements) for several years, and in 1955 a Band III converter was produced which could be fitted to existing sets to enable them to receive the new ITV programs.
The TV22's main claim to fame is that it was the first British television that could be tuned by the owner to any one of the two then current BBC transmitters as well as the further three proposed channels.
The Bush TV22 is an icon of early 50s Bakelite sets and highly desirable today, although in its day it was one of the cheapest sets available (at £35 and 10 shillings) - it was intended for those who couldn't afford a set with a 'proper' wooden cabinet. The post-war timber shortage was the main reason why some TV manufacturers used other materials for the cabinets."
Source: Science Museum Group
collection.sciencemuseumgroup...
It was sad to see so many CRT's get discarded at the end of their era. The manufacturing process is so complex, it's not something that we'll be able to repeat later on, if someone decides to make vintage components decades later. It's not hard to transform a modulated picture into an image, but to do it fully in analog mode - it's a miracle. I remember looking inside the family TV cabinet in the old days. Seeing so many components. All through-hole design. Large things. TV made a noise. Had to warm up. Everything glowed. There were lots of vacuum tubes. It was a miracle. Tech that comes out nowdays, we're used to. It's no longer special.
Hi enilenis, good points. There do seem to be some fond memories of the warm glowing hum of old radio and tv amplifiers with the vacuum tubes. Kind of miss that.
You would love to see my hoard of vintage electronics, at my house in Indiana!
enilenis, it was like magic in every home.
The engeniering solutions developed to create electronic b/w and latet color tv sets were fabulous, the lcd and plasma tvs are a mere matrix system tv sets...
Indeed, efficiency is always important, and achieving it is a goal of engineering, especially in electrical engineering.
So many variables to go wrong, so much that needed perfect synchronization, and it was all transmitted and received by good old VHF radio waves. Sheer genius in invention, engineering and manufacturing. It's amazing that it worked at ALL. Just the wave form of a B&W video signal is amazingly complex, AND it also had to carry the audio! And this is "just" B&W TV! Sure a B&W TV system would impress anyone today, But how many jaded lay people today even know HOW it worked. It's actually an amazing feat of purely analog tech!
You're an amazing feat of purely analog tech! 😋
@@marctronixx Technically speaking, That's true and even better I'm a purely chemo-mechanical analog device. 🤔
Saw your comments about tv technology. What was amazing is the work of RCA engineers to bring us color television. And because they didn't want B&W sets to become obsolete they found a way to broadcast a color signal so that B&W sets could also recieve a tv program broadcast in color. .
@@Brian-yt8fu Yes, that was not only a wild bit of engineering, physics.and chemistry It was an amazing "out of the box" pro consumer concept and one of the rare times that a new format didn't force the owners of the old devices to need to switch. This concept also happened in radio when stereo was added to FM the new stereo signals were still compatible with mono FM radios.
That was quite wonderful. Even though this technology is nearly 100 years old it is still mind blowing.
06:27 That control room I can imagine Dr Frankenstein screaming: "it's Alive!"
Television CRT where elaborate electronic air cleaners as well. I could immediately tell if there was a smoker in the house and about how many packs a day from the high voltage anode lead in a TV when servicing.
It was amazing invention, thanks for the great scientists that make our lifes better.
This is a pretty good documentary for its day. Seeing that final generation iconoscope tube was interesting. It resembled RCA's "orthicon" very closely. Note, I did not say "image orthicon" which is a completely different camera tube altogether. Not obvious about that tube is that it is magnetic deflection in only the vertical axis and electrostatic deflection in the horizontal. I built some of my first all magnetic scan systems from scratch in the past couple of years and discovered that it is extremely difficult to get them to scan at thousands of sweeps per second. Vertical was only 50Hz in their camera and horizontal scanning was 8.1KHz in the horizontal (405 scan line system of the time in the UK). That's less than half of the 15.6KHz in modern SD television. Remember these are the earliest days of post WWII television in the world.
Hi videolabguy, great point in noting the difference between magnetic deflection and electrostatic deflection! A fine point (but major one) that most people would not be aware of. Thank you for sharing that bit of info. ~ Yes, these are really some of the earliest days of television when much was still in a state of evolution. (I have a 1947 TV in my garage that is likely beyond my skill level to tinker with, but fascinating to look at.) Thanks again! ~ Victor, CHAP
The tubes used here are called CPS Emitrons (CPS standing for Cathode Potential Stabilised). These were the direct descendants of the original Emitron tubes, which were essentially a copy of the Iconoscope.
Hi Davba2, thank you! Good to know. ~ VK
Very well done film.
Did you check out the build quality of the television receiver. Almost military grade.
You know how sometimes you have an epiphany moment I just had a big one.
I started working with cameras 35 years ago and in the first 5 years we only had tube cameras, I never really knew how a electron gun that is shooting out electrons could make a signal out of photons hitting a piece of glass. I could never figure it out and the first 5 minutes of this film just made my brain go pop wow.
Q why do you never see a photon at the baggage carousel?
A Because a photon is traveling light.
Very well explained and super interesting video, Thanks!
Raymond Ste-Marie, glad you enjoyed it. ~ CH
Thank you, thank you, thank you for all of those that came before us to make this possible.
Our first television was in 1957.
Please boost your audio to a 0dB level. This videos audio level is -20.7dB level. Right click on the video then select "stats for nerds" It will show you the various items including the audio level. Great content as always.
It's amazing that they could make a tv work with just 15 or so tubes.
Intresting to see how many tubes the pictures had to pass in those TV stations which had sure drawed more power than a small village to produce a signal that ended up in a couple of micro or Pico Watt at the recivers antenna..
Wonderful footage. The explain makes everything so simplistic, for those who knows that to make it happen is way more too complex. The minimum deviation of tolerance of the values a capacitor, or a resistor, the wear of the tubes, the mains voltage floating are enough to distort the signal, with direct effect on image quality, misincronization, "ghosts", noise...
An ofcourse, the amount of energy to power up these glass tubes in heavy wooden boxes.
Total nostalgia.
Hi Brasilian Guy, thank you very much. Glad you enjoyed this vintage film on early television. We are looking for more like this and hope to find and restore similar tech videos for sharing here in the coming weeks. ~ VK
The picture tube was all round!
Yes, most were round in the early years. Easier to manufacture back then, and derived from early work in RADAR tubes.
Very nice. Thank you CHA.
You are very welcome. ~CH
There was a smell that I remember coming from our TV’s when turned on.
I remember those X-shaped aerials, and the H-shaped ones..
Amazing, I wonder if it will catch on
Just a basic explanation about how a picture tube displays a picture. There's a lot more taking place inside that tv chassis. The tv signal has to be processed before it's sent to the picture tube.
Quite true!!
very nice thank you
Hi Metin, you are most welcome 😊
Master piece of early Electrinics.this type of device was very complex and very hard to manufacturing.Gid bless our scientists ! ! !even scientists are not believers ! ! !
That was very good stuff 😃
It is in fact not 50 separate pictures every second. Two halfes (half the lines, one odd and one even) of a pictures are interlaced, giving a full picture every 25:th of a second. Thus 25 complete pictures per second, and not 50! But of course the screen "flickers" with 50 Hz!
Imagine showing this guy camera on our phones today the size of a fingernail.
British accents sounded way different back then.
What a well done documentary. I totally understood it. I’m shocked though. I always thought tv cameras had to use film. For example when filming a 1960s sitcom like Bewitched, I always thought the cameras in the studio had reels of film inside. I had no idea it was digital way back then. That amazes me. I know they would have had to transfer it to film later for distribution to the networks around the world. Or it would need to be on film to do the editing but according to this video film was not used in the cameras. Very cool.
Hi dks469, glad you enjoyed this vintage film! Hope you will check out some of our other films/videos too. ~ VK
Filmed episodes of network shows were TV scanned and broadcasted.
*Thanks!!*
Is there a video that explains how today's TVs work?
That the LCDs act like millions of window shades opening and closing?
Our videos are mostly focused on vintage technology, but we appreciate your question and may look into adding some additional modern technical info especially for comparisons. Thanks very much!
The bakelite set featured is a Bush TV22 I think. The set with the case off looks older. Lots of EF50 valves. These were readily available as surplus from WW2 radar usage. Anyone know what set this is?
Hi Eric, yes, pretty sure it is a Bush TV22 9" table top television receiver, manufactured by Bush Radio Ltd about 1952. Bush started making this model around 1950. There is more info on this in the "description" section of the video too. It was a popular set in the UK, for those who could afford it back then. : )
The set is a TV12, which was an earlier version of the TV22, being made in 1948/49 from memory. It used the same case design as the TV22.
Hi Stuart, thank you very much for your comment and info. Both models look very similar... do you know how to identify this as the TV12? I am very curious. Thanks very much. ~ Victor
@@ComputerHistoryArchivesProject The TV12 used EF50 valves, as does the one in the film. I actually have a TV22 chassis, and it definitely differs from the one in the film.
@@ComputerHistoryArchivesProject i used to have this television back then. What a golden time it was!!😭😭
The US NTSC standard was up to 480 30fps but broadcast was about 330. But Europe's PAL I believe was 576 25fps perhaps because they developed it slightly later then US, noticeably better. However NTSC was backward compatible with B&W, PAL was not but was superior color pix, namely better color with weak signals.
Most of Europe used CCIR B 625 lines in monochrome on VHF.
Ireland adopted CCIR I 625 lines and broadcast on VHF. The UK adopted CCIR I in 1964, however two networks( BBC 1& ITV) already broadcast on system CCIR A (405 lines) on most of the available VHF spectrum. Hence in the UK 625 lines ( system I) was broadcast on UHF only.( no space on the VHF spectrum) It took a while to get good population coverage with UHF. It was about 70% by the end of 1969. By March 1974 it was 94% coverage. From 1969 the BBC1 and ITV networks broadcast on 625 UHF as well. The 625 luminance signal was electronically converted to a 405 line signal and broadcast simultaneously on VHF. ( for those with old 405 line only TV's, or in areas without a UHF signal) Britain tested the NTSC ii color system with the 405 system btw, AND with the CCIR I 625 line system, and tested SECAM before adopting PAL in 1966, ( as it was adjudged the best Colour fidelity Colour over broadcast) broadcasts commenced in Colour from July 1967 on UHF.[BBC2]. From 1969 BBC1 &ITV started broadcasting in Colour on 625 on UHF. I had a portable monochrome 625 UHF TV and I can confirm it was compatible with Colour broadcasts!
The VHF 405 line system was not compatible because it was a different system. The 405 line system was closed down in January 1985, in fact the last relay for BBC1 405 on VHF (Llandrindod) was so remote the engineer was not able to get out to it to shut in down until January 6th 1985, three days after the rest of the VHF transmission network was closed. ( the relay had its own standards 625 to 405 line converter) I wonder how many people turned their 405 line TV in Llandrindod on January 6th expecting a picture?
From 1963 to 1970 most monochrome TV sets in the UK where both capable of receiving VHF and UHF and switching from 625 to 405 . In fact Colour dual standard TV sets came in the market in 1967 in the UK that could do the same!
Hi Martin, thank you very much for your detailed information! It provides a great bit of history that many do not know. I definitely learned something myself! Thanks again! ~ Victor, CHAP
In France, before SECAM, we had 819 lines Black and white. It was good but need special cameras, VTR... It was HD before HD.
You are mixing your apples and oranges. So called NTSC (RS-170A) is the color version of RS-170. Both are 525 total scan lines at 60 fields per second using interlace. A "frame" is made of two successive field scans to reduce flicker and cut total bandwidth in half (4.2MHz for the video portion of the signal). The 330 lines you quote is for vertical black and white lines in a test image. At 4.2MHz bandwidth, these lines blend together when there are more than 330 of them. Think of a camera slowly zooming back from a picket fence. So, there are SCAN lines which are horizontal, then there are RESOLUTION lines which are vertical and represent the maximum speed at which the electron beam can be switched off and on
PAL was developed in the 1960s in Germany. I had the pleasure of watching the first commercial color program on out BW 10" TV in 1967. The show was called The Golden Shot, a game show. Still popular I hear.
As for PAL "being better"? Malarkey! PAL has a slight transmitted bandwidth advantage, but us otherwise identical to NTSC in all but one technical trick to eliminate the TINT control. This was not as good as it sounds. In NTSC, phase disturbance caused the famous "purple people eaters" and "jolly green giants" problem of tint shift. PAL alternated the phase of one of two color carrier signals such that the error was purple in one line and green in the next. At the proper viewing distance, the human eye blends the green and purple back to "normal". It is ONLY an illusion. I always hated PAL screens when I had to look at them close up. One. They flicker horribly. 50Hz is just barely above the flicker threshold for most viewers. Two. The purple and green lines popped out at me and were even more annoying than the whole picture doing this in NTSC.
One of the contributing factors to the NTSC vs PAL fallacies is that the German engineers could be, and were, much more fastidious about signal quality. Since their broadcast system was paid for by tax payers, it did not matter what TV operations could cost there. In the USA, stations and networks were required to turn a profit and this always leads to cut corners.
PAL video showed up fine on BW sets, as long as the tuner was on UHF.
Tell my grandson that we used to warm up the TV before it work. Now im in a looney ward.
The software in a modern TV takes longer to sort its life out than any CRT.
So, in other words, analog television really *did* have a definite resolution size: the number of horizontal and vertical squares on the mosaic--they were the pixels!
But by the time you get to the Plumbicon tubes, you had a continuous photosensitive surface. Your vertical resolution is set by the number of scan lines - 575 lines on a 50Hz PAL standard - but the horizontal resolution is set by the frequency response of the circuit. 5.5MHz gives a theoretical limit of about 290 'pixels' - 145 line pairs - but it's tricky because those 'pixels' can start anywhere, rather than on a pixel grid as with a modern camera, so the resolution is continuous up to the frequency limit. You don't get that with a pixel camera.
The interlaced horizontal field traded time resolution for vertical resolution: if you want to think in pixel terms you're probably thinking about 290 by 290, though you'd need twice the number of actual pixels to achieve similar resolution digitally.
Comparison of digital and analogue resolution is, um, tricky and subjective.
(p.s. yes I did work for the BBC as an engineer for over thirty years).
Hi Neil, fascinating. - Over 30 years as a BBC engineer! Bet you have some unique stories to tell. : )
@@neilbarnes3557 All good stuff. I imagine this film was made in the 405 days? The vertical resolution of that system was around 377 lines.
@@neilbarnes3557 I think the horizontal resolution on 625 was about 580 pixels in effect. 290 is about the number of cycles of the maximum video frequency of 5.5MHz that would fit onto the active line duration of 52uS. But, each cycle could in effect deal with two 'pixels' as each cycle would include a peak and a trough (peal white and black level).
Notice that they never use 'pixels' to describe the picture units; that term didn't come until the early 80s, used by the computer folks. They always had to be different.
😍😍😍😍😍😍😍😍😍😍😍😍😍😍😍😍😍😍😍😍
Could you please add subtitles to this video?
Thank you, will take a look at your request. ~ VK
How many lines were there in 1952? 625?
That sounds about right. But I'd check further to be sure. : )
@@ComputerHistoryArchivesProject OK! Thank you!
Ah, happy days, nothing quite like the smell of hot silica glass valves, back then the tv was a brown box in the corner, usually wood apart from the tv22 here, it took a while to warm up and could be a bit temperamental but the programmes were great, today the technology is fantastic but the programmes are rubbish.
Love the last part of your sentence. : )
Wizardry
merc vw fleet of new freddys rev engine