How Analog Color TV Works: The Beginnings
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- เผยแพร่เมื่อ 20 ส.ค. 2024
- In this video we explore how we added color to everyone's favorite passive entertainment medium. Modern color broadcasting began in 1954 after years of experimentation, and this video will teach you the early history.
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I'm old enough to be your grandfather, yet I learn something interesting from your videos every time I watch one. Thank you for the research and sheer effort you've put into "Technology Connections." Your videos are very well done and fill a void of knowledge on TH-cam.
what an interesting mathematical conundrum
@@mr.worldwide5211You rock
You wish he was your grand son. And not the other kid that..
@@grilleFirewhat?
My grandpa worked in an appliance store. A perk of this is that he got a color television set at home to work on. His was the only color set on the block, and people came over just to see it.
I don't know why, but I find it kinda funny to imagine a line forming to see a TV in color
@@minix07 I don't think a line formed. Nevertheless, the local residents of the street in Vancouver seemed to come over quite often when he got that television set...
@@infinitecanadianlol
Yeah when I was a teen I had a B&W tv and I hooked up a vcr to it. I would play the my recording on my B&W set. I was young and did not know that I was not recording what showed on the TV but the signal that came through the cable. I was shocked when one day I took one of my recordings and played it on a color set and the picture was in color and not the B&W I thought I had recorded.
I had the opposite. My VCR had a tracking problem and wouldn't play or record in colour. Which was never noticed, because I had it hooked up to a black and white TV. The real shock was when I brought a tape to play one someone's colour TV and it was still black and white!
Sounds like a memorable experience!
I always recorded at the worst quality to get the most amount of hours. :)
I had a hard time reading this
why B&W tho
@@probnot old comment but information is always good so: Sounds a lot like a PAL-M problem. We Brazilians have this a heck lot. Nowadays to capture video from analog sources we gotta find some stuff that can actually accept our clever but annoying mess of a video signal. PAL-M combines the black and white frame of the NTSC format (that is, what it uses as the frame, I know NTSC is the color system not the black and white frame itself), but with the PAL color system, on a frequency that works on NTSC frames. It's hell. Sure, it had the best color system of the two and the faster framerate at once, but nowadays... what happens is that Brazilian recordings look black and white on NTSC gear, and jump or don't show at all on PAL systems, unless maybe the other weird PAL-60hz system... and I have no idea what that one is.
And now, me here trying to get old Video 8 tapes out of the dying camcorder, gotta deal with that crap years after their common use demise... "fun" fact: many capture cards can do either PAL or NTSC, but when that mess pops up, it either does nothing or shows black and white.
RGB and 144Hz? Man those guys were hardcore gamers.
Tom5tom Entertainment :) I wonder what FPS they we're getting on Crysis with their sweet Univac rig...
MOS6582 when i see 80’s shows i see it as a very high fps but when i see shows now it seems like its lower then the 80l’s framerates.
TV shows in North America in the 1980s were 30 frames per second. This may look faster than some modern TV to you for two reasons. The first is that the picture was interlaced, drawing every other line 60 times per second (controlled by the 60 Hz power supply). This is essentially a compromise between 525 and 262.5 vertical resolution (minus some for overscan) and 30 fps and 60 fps time resolution. The second reason is simply that some TV shows now really are shot at the lower 24 fps rate for a cinematic quality. However, you will also find some cable and satellite broadcasts at higher frame rates, up to 240 fps progressive scan, which would have been impractical in the 80s and impossible for broadcast TV.
@@EebstertheGreat I might also want to add that audio and video, compressed, are not compressed together. By extension, they're not decompressed together either. They are completely separate streams that need to be synced up at playback, and they are not inherently in sync. Although modern video(with audio) transmission tries to sync it up, it's not always successful, and not nearly as "perfect" as it was in the analog world. I may be aging myself(and I'm not THAT old), but I still notice the subtle lip syncing problem when watching videos on TH-cam and even digital TV, which is pretty much everywhere now. IMO, this accounts for some of the "80s frame rate seemed better" perception. SMTPE ST2064 addressed this pretty recently in 2015, but I'm not sure how much that has been rolled out or implemented.
I'd be interested in hearing if younger people know what I'm talking about.
@@djd829 It is true that the audio and video streams are separate, but this isn't the source of the desynchs you are seeing. That is really common on TH-cam and many streaming platforms, but you shouldn't see it on videos on an optical disk. The problem there is the way the video player handles video and audio when buffering. If a video pauses to buffer, you will often notice the audio continuing significantly after the video has paused. This is because the video signal is much higher bitrate than the audio, and so if your internet connection to the site isn't fast enough to keep up with the stream, the player usually runs out of video to show before audio.
In principle, there is no reason the two couldn't resynchronize perfectly when the video starts playing again, but in practice, this is where I've seen things go wrong most of the time. It's just a software bug, and if you download a video entirely in advance and then play it, you shouldn't experience the problem. The desynch is not a problem with the video container.
If digital TV is giving you issues, again, it's most likely a software problem. My parents have a very high end setup, but because the sound is handled by a separate device from the video, the two can desynchronize. I think in this case you are basically right, though it has nothing to do with compression. A totally analog system will introduce practically no delay between the signal coming in (from a tape, broadcast, or whatever) and the mechanical motion at the other end (of the driver, CRT, or whatever). It's impossible to have this sort of problem with analog equipment, assuming the video and audio equipment are getting the same signal at the same time. But digital devices necessarily introduce a delay, because computers are only so fast. In properly-designed setups, this shouldn't ever be perceptible, but it's something that often goes wrong that never did in the past.
I never was able to understand before how color TVs were able to light up their correct red, green or blue "pixels", even after reading a lot on Wikipedia and various vintage television sites. Your explanation of the shadow mask, the angled effect and the fact that color CRTs have no actual pixels was easy to comprehend and it makes total sense to me now. You've earned a new subscriber and I'll look forward to new videos from you, and to going back and watching all of your old ones.
I'm too
Possibly the best 'tech explained' videos on TH-cam good sir. _oh and I always love your dry sense of humor!_
Baird's solution to everything: get a massive disk spinning at dangerous speeds.
Why use a normal umbrella when you can have a buzzsaw blade attached to a power drill over your head?
I had the same thought :D
Hardly surprising that his landlords had a habit of booting him out due to explosions and the like!
Andrew Gwilliam Wow, cool. A true mad scientist! He sounds interesting, as would his roaring mechanical color television. You could FEEL the color.
The disk has survived until today.... in any DLP projector.
well he invented more than you
When u made yellow from red and green, I could actually see green in some parts of my peripheral vision, SO AWESOME!!!!
The back part of our peripheral vision is actually black and white because only the rods of our eyes can see that far. Of course our brains do some fancy stuff to make it look like it's in color.
When I see a white text on a ps4, i can see red and blue
@@windestruct do you wear glasses? That may be the chromatic aberration caused by the lenses. Source: I wear glasses
@@samueltufts I think it is a special effect and i dont wear glasses
@@windestruct you need a new TV.
Man, I love your videos. It’s awesome to see someone take the engineer guy’s formula and apply it to electronics. I’m increasing my patreon contribution. You definitely deserve it.
#spoilers
"Hiding the colour in plain sight" meaning that the colour in a Composite signal is directly modulated onto the original "brightness" signal, but using a higher carrier frequency. ;)
A black and white TV would usually do a pretty good job of filtering out that added carrier, due to low-pass filtering of the luma signal.
Superb vid btw, as always. :)
Judging by your comment, it sounds like you are very knowledgeable about this stuff. If you have a minute I would be very thankful if you checked out the comment I left at the top of the page. I have been trying to better understand what my grandfather worked on at RCA in the 1950's. Either way, good job figuring out the cliff hanger at the end of the video, cheers.
The low-pass filter wasn't always low enough to eliminate dot crawl.
Yes, that is quite true, a phase-modulated color subcarrier, to be specific :). A quite ingeniously-engineered solution for color television, and all-electronic even, no spinning color wheels or any of that crudeness ;) .
But I do have agree with Scott, composite video does suffer from that dreaded dot-crawl! In my video tinkering, I've noticed that some monochrome composite monitors made for CCTV and older computers (like your Apple IIs, etc.) tend to exhibit dot-like patterns all over the display's raster when color video with burst is displayed. I tried another video source that for sure I knew was monochrome, having no colorburst and no color subcarrier, and it looked clear as a bell, no dot-patterning. I guess those monitors displaying the dot patterning lack the proper video filtering (maybe due to manufacturing cost).
Ryan Schweitzer
Yes, maybe I should have said that the filtering is not ideal on some monochrome sets.
(where the filtering was more of a side-effect of the limited bandwidth of the transmission itself.)
The dot crawl or "running ants" effect can be quite bad on colour sets when fed via Composite too, which is why I always tried to use RGB SCART on my retro machines, even back in the late 80s / early 90s.
Newer TVs (analog broadcasts) often employed a 3D comb filter, which reduced the dot crawl a fair bit, but also not perfect.
There's an interesting article online about a PAL transcoder which gave superb quality from old tape archives, like Dr Who etc.
If I find it again, I'll post the link here.
Jacob Marker
I'm having trouble finding your comment, as I'm using an Android box atm, so the comment ordering is a bit weird.
Could you possibly give a quick summary here?
I really enjoy your videos. You have a great voice for teaching/instruction..
Might be the worst part. Can't stand listening to him talk.
I like his voice too. He's also funny.
Somethings I'd like to point out. Guillermo Gonzales Camarena's color wheel patent actually predates that of CBS and his device worked rather well. Camarena's original patent was in Mexico and appears to have been submitted in late 1939 and was granted in August 1940 before CBS patent submission or demonstration. I have a scan of this certificate and can send it to you. His US patent also recognizes the Mexican patent date and also makes everyone think that his invention came after CBS. Camarena's system worked well enough to be used for medical equipment and studio broadcast equipment some of which was exported to the US for the columbia college in Chicago. Like CBS, Camarena's system was not necessarily limited to the 30fps standard or it's field rate. Only having to use it with a current broadcast standard was a limit he considered. At the time those standards were not set in stone so I'm sure he knew of higher potential. He was often building closed circuit equipment so he may have exploited that to his advantage to avoid norms. I recognize CBS system's advantages but Camarena was truly the first to demonstrate that practical color TV was possible, especially considering it's compatibility aspect. I've seen footage of his system and it's functional. I also have an interview of a former NASA engineer who says Camarena's color wheel system was inspiration of the color cameras used in the Apollo moon missions, his name is Paul Coan and says this on a documentary. It's a shame he's so badly documented. If you would like to know more please contact me. :)
It may be that Guillermo Gonzales Camarena's system predates the work of CBS, but John Logie Baird had a mechanical sequential-color TV working in 1928. I don't wish to suggest that Camarena's work isn't important, but it's very hard given knowledge of other people's efforts for me to credit him as the "Inventor of Color Television" as some people do.
Hello, you are correct, that is indeed a mislabeling. Camarena didn't claim to have invented the first color system ever either. In his patent he mentions how at the time color systems were very complex and expensive so he knew of prior works done in the field but his invention was supposed to be a practical alternative. Baird's technology was still nipkow disk and other all electronic experiments had high cost and other large issues at the time. I do believe he deserves this credit, first practical system. Which although not as practical as the later NTSC standard (I wouldn't want to have a spinning wheel for a TV either) did break ground in putting color at reach for the public with results superior to all the previous systems except maybe the tri-tube systems at a very reduced cost all while being compatible. I am currently working on a documentary on Camarena and have spent months undoing bad documentation and digging up as much detailed information on him as possible. Camarena died in a car accident and the people who came documenting him after this didnt do a very good job of it except for an engineer that worked for him. Currently his sons have a large collection of information which includes plans for his inventions and I assume technical notes. I am trying to get in contact with them. His bi-color invention was also not the first to use this sytem but was taylored to a significant cost reduction that was more than just a few dollars as the CRT featured no shadow mask and the television had no chroma circuit. This system was about to go into production by majestic before he passed away. Stay tuned for my docu, it wont be a proper documentary but I do aim to clear up the history on him with more exact facts than the usual texts you can find online. I hope to clear up a lot of questions.
He was in Mexico so that was a Mexican patent, and that doesn't count as first in the USA (where it actually matters, since patents issued and good in 3rd world shit holes aren't worth much in the first world without a patent there as well). Regardless, considering all patents issued that far back have long since expired and the ones applying for them are long dead who cares who was first? I'm sure Newton wouldn't care if Boyle actually got credit for discovering the mechanics of gravity and neither would Boyle himself, both being dead for centuries and all.
@@fvckyoutubescensorshipandt2718 Camarena Patent his invent in both countrys
you guys just make Mexico look bad , you guys also claim to have invented electricity
The word "pixel" comes from virtual square tiles used to assemble pictures on a computer. It's a software thing and they were made square because it's easier to apply the logic of matrices to them and also other mathematical concepts... But actually they could have any shape... It's just very hard to immagine how non-square pixels would work.
Pixel is very much a computer term made popular by the computer nerds in the late 70s. Before that, it was called the 'dot matrix' (or dot pitch) that made up a picture. Today, very few even know what 'pixel' stands for. (In Europe, they called it 'pels.')
Never heard of "pels"
//European
“Pixel” is a portmanteau of “PICture” and “ELement.” Pix is a throwback to a 1932 Variety magazine usage of “pix” as an abbreviation for ”pictures” used as a reference to movies. By 1938 it had migrated to use by photojournalists as a reference to still pictures. Pixel was first published in its modern case by Frederick J. Billingsley, of JPL, to describe picture elements of scanned images from moon and Mars space probes. Billingsley said he had heard it from Keith McFarland, at the Link Division of General Precision in Palo Alto, who in turn said he didn’t know where it had originated, only that it was, “in use at the time” (circa 1963).
"It's just very hard to imagine how non-square pixels would work." May I offer a suggestion? :) :D
How about hexagonal (honeycomb) pixels? Firstly, they all fit flush together. Secondly, and I don't know what "significance" this is, but they could be "accessed" via three different angles/axes. A square pixel can be identified through two coordinates, (x,y). That's because you have two directions, or planes, or axes or whatever, of symmetry in a square: "up/down" and "side/side". With a hexagon shape, There are three ways rotational symmetry: "up/down", "top-right/bottom-left", and "top-left/bottom-right".
At this point I'll say, I don't know what the particular pros and cons of this would be in regards to applying the logic of hexagonal matrices into computing. Obviously it makes it more complex, but it does make me wonder "how well" it would!! Anyway it was awesome to learn that "pixel" originates as a software term :)
Since somehow nobody has mentioned it, pixel aspect ratios that aren't 1:1 are not too common, but they aren't impossible to find -- the Amiga did it, for example. All the examples I know of are still rectangular though.
5:29 Something tells me this Baird guy was popular at nightclubs.
9:04 The guns are actually very close together in the neck of the tube, so the angles of the beams would be almost identical if they followed straight lines. But since the trajectory of the beams is controlled by a magnetic field which tends to curve the beams in a way that is affected by even the small distance between the guns; the beams end up curved in 3 directions, making the shadow mask much more effective in directing each beam to the appropriate phosphor spot.
he did write that the angles were exaggarated
Love these videos, but adding the PS1 startup sound, was the icing on the cake for me. Love that sound.
James Siggins Don't forget the anxiety hoping your disc isn't hoopajoobed during that inevitable pause between the PlayStation logo and the game actually starting!
AirborneSurfer those were the days. :-)
AirborneSurfer The anxiety was between the Sony logo, and the PS graphic. If you reached the black screen, the game was likely to load. There were few worse feelings than getting the blue background generic menu screen instead.
And that _PaRappa the Rapper_ stinger (13:06)
Let's be honest about "Never Twice (the) Same Color".
By about 1975, US broadcasters had figured out how to keep their color burst signal in the correct phase. Set the hue knob to show the grass is green on any channel, than leave the hue knob alone after, and the color would be fine on all the channels.
You could also use the SMPTE color bars that stations used to broadcast before going on air early in the morning. Some cameras can also provide color bars, or you may have a channel on your cable service.
1L6E6VHF Yeah, but it took nearly 30 years to figure that out and by then PAL had been working great for 10 years.
Wasn't the issue due to multipath interference? So you couldn't simply get round it by setting things correctly at the broadcast end.
NTSC = NEVER THE SAME COLOR! (or, Never Twice the Same Color, etc)
I always thought the description of SECAM as "System essentially contrary to the American method" was funny.
PAL = Perfection At Last
Personally, I always preferred this meaning for NTSC:
Not
The
Smartest
Choice
It's the curse of the perfection. PAL was derived from NTSC but corrected the issue of colour stability. SECAM (means séquentiel à memoire: sequential with memory) was derived from PAL but used another method to store the colour information from one line to the other, solving one of the problems PAL had. Solving this stability issue also made it very difficult to tamper with the signal and made keylock and green screening essentially impossible.
Yes, I ve heard that due to those difficulties and limitations of SECAM, most European TV studios that transmitted in countries that used that standard, like France where it was developed, would just use PAL color video internally in their plants for production and preparation for air, and then convert at "the last mile" to SECAM into their transmitters for over the air broadcasting.
IMO, SECAM is weird and unique in how it uses a memory of sorts (using analog delay lines when SECAM was developed, IIRC) to keep the color in check. SECAM almosts seems like it was a bit too ahead of its time---such a standard would be a cinch to implement with today's digital (and analog) electronics. I wonder if most later-era SECAM-standard TV sets probably had some digital circuit or buffer to process the SECAM color info.
It is very French, make something different but essentially the same so it is ours. PAL was an interesting standard, it had a higher resolution than NTSC, which is basically due to both systems being based on the AC power frequency of where they were invented. This gave NTSC a higher field rate and PAL more lines to a field for the same bandwidth. Due to this and PAL later being stretched for anamorphic widescreen meant that America was quicker to take up HD, as in Europe what we had wasn't as bad.
I am in complete awe! I had to subscribe. Thank you so much for these extremely informative and rich videos! You sir have got to be the most well documented person out there. How are you able to deliver so much content without skipping a beat is beyond me. Enough said, let's watch !
The rotating color wheel is also how DLP sets work to produce a color image.
Unfortunately, though there are some designs that do without it. But DLP is inherently mechanical even without a spinning wheel. All those little mirrors--yuck! Such a mess onscreen when they start failing too.
Yes, projectors work this way, and when you move your vision from left to right you will notice a flirck, like strohoscopic effect. Same when you see a rear tail light in a car, LEDs are strobo also, and you will notice a rare flirck
I had a big 20" trinitron monitor back in the early 2000s and it was awesome for the day. I still remember those two shadow line wires some people would complain about. Looking forward to the video on this.
Seeing the PlayStation logo on a CRT screen gave me a shudder of nostalgia. I used to play mine on my old UHF set with an RF adapter.
I don't really understand or care about the topic, but it's nice to see someone so passionate and knowledgeable about something. You obviously put a lot of work into this, good work!
> be about to go to bed
> New Technology Connections video
> who needs sleep anyway
time zones!
adigyran No, just getting off a night shift :p
Nothing like that 17th cup of coffee.
Technology Connections, Lazy Gamer Reviews, Techmoan, The 8-bit Guy, ... Aaaaand I drop the phone on my nose again, semi-conscious.
danijel3672 I'd add Big Clive, Ashens, and possibly Guru Larry to that list myself.
This is great - now we wait for the videos on color for PAL and NTSC I guess ;) Also - please consider covering FM stereo as it is a pretty interesting topic as well (the whole multiplexing system).
FM Stereo and SCA subcarriers, and often forgotten, (and even unknown by the younger generation)... AM Stereo of the 1980s. Again, just like color TV, and video tape formats, AM Stereo was plagued by four "standards" being broadcast, with C-QUAM ultimately being the winner.
From the 1970s, another interesting fad was Quadraphonic, with amplifiers/receivers using tapes, records and even FM broadcast decoding for four channel audio.
indeed :)
This man looks like a nerd, talks like a nerd and it's one of the coolest man I want to hang out with XD
i dont think i have ever made a comment like this before on youtube, but that bit with you speaking through the CRT was a realy nice touch
Never thought I would be so interested in this topic, but gosh darnit, I just had to subscribe to see the next part!
Looks like I'm years late to this channel. What a gem. I've been sharing many of them with my old dude friends
Surprisingly accurate and in-depth exploration of analog color television in the USA.
aa Thank you so much for the amazing content. It's so refreshing and reassuring to see that in this age of dumbed-down rubbish that plagues almost every media outlet, there are still some passionate people dedicated to producing interesting, high-quality content. I love your videos and can't wait for more. You make the world a better place with your work, and I wish you all the success you deserve for it
I hope the next video discusses restoring color to lost Doctor Who episodes!
Awesome video! Thanks for all the research effort.
TH-cam member 'Spats Bear' is in the process of a full restoration of an RCA CT-100. Apparently the CRT still tests full vacuum and 100% emissions with Sencore.
About that CT-100 tube: "They don't make'em like they used to!"
TH-cam usually blocks *me* from posting links, but if they don't block me, here is the link to the CT-100 restoration video: th-cam.com/video/q-tuykV6HBg/w-d-xo.html
Darn! Im already in the middle of 2 Xerox Alto restoration videos! Guess Ill have to watch them all at once
I have heard of that guy from somewhere ;-)
Fantastic video! Probably the most comprehensive and detailed series on how analog TV works. Would love to see you tackle the different TV systems like NTSC-J, PAL and SECAM in future episodes.
As much as I love the videos, the fact that the comment section is always positive/constructive is icing on the cake!
I feel like this was probably not the best video for someone who knows very little about this topic to jump into, but I got along well enough with some additional googling. Thanks!
Hello from Australia 😀 Your videos are very technically adroit keep it up 😀
The high power of the color electron guns and the fact that most of their beam hit a metal screen was a reason a lot of color TVs put out a substantial amount of soft X rays.
Baird loved using wheels, huh?
It was his system and he was going to make it work come hell or high water!
No, not really. He continued to work on it when it was still the best system, but when electrical systems came round he started working on them instead. He invented the first all electrical colour system, and the first mechanical system!
His discs came first, and were still good until CRTs became common. If you wanted colour, his discs were the only way until the 1940’s when NTSC came out and in Europe you needed to wait until the 1960’s.
He was wheelie into them.
I wish i was this interested in stuff back when i was still in school, i mean just today I learned more by watching random youtube videos than i did in a full month of school....
Yes I have learned incredibly much watching youtube videos, even extremely complicated stuff about quantum mechanics and similar explained in ways that was possible to understand intuitively.
Just to minimise any confusion, the screen showed here was an 'inline' tube which doesn't have a delta gun arrangement (as described), it offered improved linearity and set-up ease. As described the delta gun tube did have a triangular phosphor arrangement. The PIL (precision in line) was a later development and also used in the Trinitron tubes (which used wires instead of a perforated steel plate, this gave a brighter picture, as less power (20W) was lost in the mask). A magnet could magnetize the shadow mask itself and permanently cause misregistration of colour. This is called 'purity' error. A big demagnetizer can be used to correct this in most cases.
Back in the 1970s as a late teen when I was repairing televisions, they had the delta triad electron gun and shadow mask, with Sony being the exception. If you looked closely at the front of the screen you could see the triad of red, green and blue phosphor. I don't remember when I first saw the inline picture tube, but by the 1980s the delta/triad picture tubes were largely replaced by inline tubes. The TV store I worked for at the time sold RCA, Motorola (later Quaser, then Matshuita/Panasonic), and Sony. I remember going to RCA service seminars where a field engineer explained the new precision in-line tubes. I also remember that the inline televisions were brighter than the delta/triad, but not as bright as the Sony Trinitron. I had one of the very early RCA 21" color televisions with the round picture tube. Even though it was rather finicky I wish I still had it :)
I'm hoping the next video will explain that the color carrier is actually two signals (I and Q). Every explanation of NTSC color I've read only explains the I signal, as if color is just one axis and not a circle.
The benefit of using QAM for the color carrier is that you can modulate two signals instead of just one. That greatly increases the color resolution and it would have increased it even more if both signals had been encoded in VSB. For some mysterious reason, Q in encoded in DSB, confining it to half the bandwidth of I.
Dude. Your "dry" sense of humor is PRICELESS!
All of this developments owe their existence to the invention of the tri-cromatic television system invented by Guillermo Gonzalez Camarena.
in your fantasy world
I replicated the the 3 colour process on black and white film that Sergey Prokudin Gorsky did as a project for photography class, that was a fun time lol. Awesome you mentioned him
What about the beam index, or indextron tube. Full color without a shadow mask, and only 1 electron gun.
12voltvids that was an awesome design! I remember these from my days at Thomas Electronics.
Mike H
I have a beam index projector. A Sony videomagic. It has a built in betamax player as well. These things are as rare as hens teeth. You can see it repaired on my channel. Very cool piece of technology and it actually works quite well. With the proper screen and in a dark room it has a very watchable picture.
Always wanted to see one. The previous tube company I worked for tried making these. I had an idea trying to improve the resolution by tevising the electron gun to 5megapixel type medical imaging electron gun. Never got around to it.
Beam index or Indextron eliminated purity problems, convergence errors, and were far more efficient because they did not have the losses associated with the shadow mask or aperture grill in the trinitron. They are more complex though, because they require the PLL circuit to accurately time the time division switching for the RGB video signals, and they require the 4th UV index stripe which is located between the blue and red stripe if I remember.
Due to the fact that the tube has to be biased to get the index stripe glowing even on a black screen, they do not have as good contrast as a conventional tube, and the 4th index stripe tends to lower resolution. If they could have acheived the same picture quality of the shadow mask tube I am sure there would have been more models made, but in reality the quality just wasn't there. They were good for specific applications, that being a very bright tube, such as in projectors, but no good for low light applications because of the constant glow when displaying a black screen.
Here is a link to an indextron projector repair I did on my channel a few years ago. These are cool projectors and very rare these days. Especially the one I have that has an integrated Betamax recorder. These were never sold as consumer devices, and were uber expensive back in the day because, well they were the very first truly portable video projectors that could be basically just pointed at a screen, the focus set, and watch TV or a video.
th-cam.com/video/4ApuK6YAzuM/w-d-xo.html
What??
At 10:45 great Marshall Applewhite cosplay. The soft focus of the analogue signal and background really match. 😋
You're the best, man. Great topics, great research, great summary.
Oooh, oooh - do closed captioning in analog systems! The between-frame space.
I think you'd also be interested in the history of the radio station WWV, if you're unfamiliar.
These videos are super helpful. I bought a DWIN HD700 CRT projector a while back, and I've never fully understood how it works (until now). So thanks!
I dare say that few people my age who ever worked at all with computers would make this mischaracterization about pixels. We remember the evolution of early PCs, and how they couldn’t do what a color TV could do: give you full-motion video and all the colors of the spectrum. We started out with four-color CGA, progressed to 16-color EGA and 256-color VGA before we ever got to anything that looked even remotely as life-like as what a TV could show you, even though a VGA image might be much sharper and more vivid. Anyone who bothered to ask “why is that?” would have learned that every element of the image on a PC monitor had to be individually addressable by the CPU or graphics controller, and so I bet most people my age learned about pixels from this question. It was the essence of the answer, as you couldn’t explain why without explaining what a pixel is.
I have an NTSC TV which uses a field sequential display. It has a liquid crystal shutter in front of a B+W CRT. It was made by JVC in the 1999. It is only 4.5 inch diagonal.
From the owner's manual:
"The LCCS Video Monitor is a combination of a black-and-white cathode-ray tube and liquid crystal color
shutter (LCCS), which are used together to reproduce color images.
The video signal input to the monitor is demodulated into RGB primary color signals which are then
stored in the field memory. Signals in the field memory are read three times faster than the input video
signal is, and are displayed on the black-and-white cathode-ray tube in the order of R, G and B. (Three
images are displayed during one field.)
Color filters on the liquid crystal color shutter change according to the displayed primary color signal,
transforming the black-and-white images into R, G and B primary color images.
Because of the phenomenon known as persistence of vision, the R, G and B primary color images appear
as a single color image to the human eye."
I remember as a kid once what would happen if I put a magnet near our tv screen. While the colour distortion looked pretty, I panicked when I couldn't get rid of them. I thought I was in trouble. But then my Dad came in and just unplugged and plugged the TV and it was back to normal. That was my first introduction to degaussing and it gets rid of any residual magnetism caused by idiots putting magnets near the screen.
Funny I did the same thing. We had a trinitron set at the time and I was messing about with the picture using a powerful loudspeaker magnet. I remember making distortions and weird colours and even "black holes" in the picture. Then the colours were permanently stuck. I was horrified that my dad would find out, though my mum was pretty cool about it. In the end the colours reverted to normal, but only after the set was turned off an on a number of times.
I'm so glad I found this channel, man. So many interesting videos about things I actually care about!~
I'm so glad you can get a full on education right from TH-cam these days. College & schools got some competition
I love that you wore a dark orange shirt in this video.
The colour TV system used on later Apollo missions used the spinning disc trick for achieving colour TV in a camera light enough to go to the moon. You can tell because you can see a rainbow effect around any object that's moving with anything above a very slow speed.
The colourwheel approach didn't die when RCA's system won out, and it's still in extremely common use today: all consumer-level DLP projectors use basically the same system. They have a single DLP chip that produces a monochrome image, and they spin a colour wheel in front of it to produce alternating colours. For this reason, if you move your eyes quickly to the left and right while looking at a DLP projected image, you'll see a smearing of colour known as the "rainbow effect".
Higher-end (professional) DLP projectors like you'd find in a movie theatre get around this problem by using three separate DLP chips with fixed colour filters.
I hate the rainbow effect on DLP projectors...
That lousy tech is a good reminder of how close we came to a crappy mechanical color-TV system.
Not all DLP sets! The ones that use LEDs for the light sources have separate red, green, and blue LEDs, and no color wheel. There is still just one DLP chip, but the "alternating colors" is done by switching the LEDs on and off. This is done at a far higher rate than a color wheel could achieve, so there is no rainbow effect.
It isn't nearly as bad as the mechanical color tv, because the dlp chip and color wheel are quite small, so the wheel can spin quite fast.
super high quality production, even better than on tv.
I loved seeing the Play Station startup screens with sounds. Thank you.
absolutely great video, interesting and well explained, thank you
i'm surprised you don't have more subscribers, you definitely deserve hundreds of thousands more
Big fan, hugely grateful for your content! Just wanted to say this ;)
John Yogy Bear. He sounds like him and BooBoo would get into alot of trouble with the Park Ranger for stealing picnic baskets.
I was really hoping this was the "color burst" explanation but I'll definitely be staying tuned for that!
10:40 This is why the picture looks more smooth and nicer for old video game systems on a CRT than the boxy image they have on an LCD TV.
It's always fascinated me that Westinghouse was the FIRST to sell a set based on the RCA system before RCA themselves. I got to see the first "set" at the George Westinghouse Museum in Wilmerding, PA (80% of my family worked for the various Westinghouse companies).
Thank you for explaining that these are NOT pixels; it's a dot matrix. Unfortunately, the computer industry invented this term, as they just had to be different. The term 'pixel' stands for 'picture element.' There's nothing in that word that indicates anything about the red, green or blue dots as being 'addressable.'
Pixels are really what the software deals with, as opposed to the screen itself. There is a distinction, particularly as computers could display on the same screen at the same scan rate using a different number if pixels.
When I saw that clear of an image from 1912, I felt like I'd just watched grandma climb the stairs in 5 seconds.
I own a trinitron, so I hit the bell icon so I can be notified when you explain how it works
I feel so old but RCA television was used at my elementary school. Being publicly ran and funded, they tended to use slightly older technology so even though it was the mid 2000s they used RCA TVs and I could remember a distinct purple hue when the magnetic white board was a bit too close.
Great video as always.
I know this is an older video, so you may not see this, but am interesting note is needed.
The color television cameras used on the moon during Apollo used a rotating color wheel to create the color video sent back to earth.
Dude, couldn't find your channel anymore. Glad you showed up in YTB's suggestions :D
If you press pause/play rapidly when he does the demonstration at 5:26, you'll always catch it on a solid red, green, or blue tint.
NTSC = Never the same color.
I’ve actually seen footage of the old CBS system. It looks way better than NTSC did at the same time. And that’s seeing it through a camera! In person, it’d look way better.
I’m so glad I found your videos! These are so interesting.
Feels weird to see a picture from 1912 with the world in color. It's like I feel the real world was colorless back then
Ahh apparently I am a dumb ass.... I didn't realize he just uploaded this video and went around looking for the next part. 😜 i guess I should have checked the date of release. Oh well can't wait to see the next part.
This is a fascinating review of something I just took for granted (the movement from B&W to Color)!
My late friend Sheldon Haas disclosed a way to make field sequential viewing a lot more compact than with a color wheel: Mylar sheets between rollers. This could be done with a profile just slightly larger than the screen, assuming some buffer rollers at one side. However, it would also have required large areas of the Mylar roll to be colorless (so only one color would be filtered thru as the roll doubled back on itself) and a really long blanking interval. Alas, this was in the 1990s. I later worked out a way to do without the clear portions, by wrapping the roll entirely around the display, so only the color passing in front would be...in front. Still either a long blanking interval or opaque black portions on the Mylar.
Excellent work mate.
Interesting... When I studied in Mexico, every single teacher I met was 100% positive and assured everyone that Color TV was in fact invented by Guillermo. Without any concrete evidence and completely leaving out everyone else working on the same thing.
Compare who the British (Wheatstone) and Americans (Morse) say invented the electric telegraph, and who invented the practical incandescent lamp (Swan/Edison).
hey man, good videos. keep em up.
If you want to get to the point TL;DR down below:
Luckily TH-cam didn't fail for once. Some advice, anything you're going to do a multi part video(well videos) you should create a title and then also put part 1, 2, 3, etc or something like that with the title of the video. Because I can not tell you the amount of times someone had multiple parts to a video(s) but since I wasn't subscribed to them when it was coming out I gave up on finding what videos to look for because I would have had to gone through all their videos that came out from the first video onwards... if they had even finished/continued it(since we all know that sometimes youtubers give up on some projects).
TL;DR:
So please, put something identifiable with any video series in the title of it so it can be searched for because TH-cam is FAAAAR from perfect as you should easily know as a content creator.
6:00 you must be spanish you nailed that pronunciation perfectly... or at least Italian lol
Loved how early colour tube TVs were such excellent X-Ray machines (at the back of the TV) from the shadow mask that made it past the glass! :)
I just found your channel and I couldn't be more happy! You create wonderful content, I subscribed!
The demonstration at 5:26 properly cracked me up :-D
There's only ONE superior TV standard, my old PAL. We nailed it :P
These videos are fantastic. Thanks!
Now we learn to appreciate every pixel of the fone's LCD 😁
@10:53-11:05
*Nostalgic PlayStation Boot Sequence* 🎮🤗
Great video, though I’ll probably have to watch it again to get a full understanding.
Amazing video, as always. Thank you.
I actually own a RCA colortrak which was manufactured in July 1992 and I love it
Perfect for retro games
Pulled a fight club on us with Parappa the Rappa. New sub just for that.
I used a strong lense from a camera i opened up to take a look closeup of my screen when you showed the yellow, i can confirm it is equal parts of green and red
Nostalgia. The ozone smell the tube gave off when starting up or shutting down.
Jeff Hurckes I had a brother who got his mouth full of water, then spit it into the back of our tv set. YOU TALK ABOUT SMELL?😥😂
WOW! Congrats on reaching nearly 40k subscribers! That was incredibly fast.
The loss due to the shadow mask is why the flyback on a color TV cranks out over 200 kV. If we thought B&W TV's were bad touching the wrong places, color TV's took that lethality to a whole new level. We're getting into power line distribution voltage territory here (though the amperages are substantially different since in a tube it's the voltage that counts not the amperage so
the flyback in a color simply exchanges amps for volts with additional secondary windings).
And 200,000 electron volts into a metal mask puts out hard X-rays -- I was wrong elsewhere when I wrote that they were soft -- enough to penetrate the glass of the tube.