Anti-erasure and carrot juice: on the history of color television

Is the attempt to stop the download of files on the Internet similar to the attempt to block the color on Israeli television?

A few weeks ago, an important, truly historic legal debate ended in the United States. In the trial, organizations to protect the copyright of musical works, songs, sued a woman who was accused of pirated file sharing - she allowed people to download a few dozen or even a few hundred songs, I'm not sure, from her computer using file sharing software. She was found guilty, and was fined something like two hundred thousand dollars, which is a really serious and even cruel amount.

The reason I started with the story about the trial that took place in the United States, is because there is a clear attempt here by the music companies and the copyright protection organizations to try to fight a technological process that, in my opinion, is clearly irreversible.

File sharing via computer networks is a technology that has spread around the world like strep throat in kindergarten, and believe me, from experience, the only thing that spreads faster than strep throat in kindergarten is another strain of strep throat. Any child from the age of four can share files, it is very easy to write programs that know how to do this, and the anonymity of the Internet means that file sharing, according to all signs, is not going to disappear and even on the contrary, it will only grow and grow and expand.

If there is such a thing as a losing battle, it's the battle the music companies are fighting. Their chance of stopping this phenomenon is about the same as putting out the fire in this giant giant giant field of thorns with a splash of water from a spoon.

Don Quixote had a better chance against windmills than record companies catching every 8 year old downloading Britney Spears songs online.

And that brings us to another lost battle, which is the battle waged by the Israeli government and the Broadcasting Authority against the possibility for Israeli citizens to watch color TV broadcasts in the seventies. Perhaps it is more correct to say that it was only the Israeli government that waged this war, on its own citizens, because the Broadcasting Authority is merely an executive tool of the government's policy in this respect: like the Tax Authority, for example, does not collect money for itself, but for the state. At least I hope so.

Until around the mid-seventies, the vast majority of television receivers in Israel were receivers that only knew how to display black and white. This wasn't a problem until then, because the vast majority of TV station transmitters also broadcast in black and white, so even if you were lucky enough to have a color TV anyway, you still saw the picture in black and white.

But in the mid-seventies or so, a process began in which many television stations in the world began to switch to a color transmission method. The Europeans started broadcasting in color at a relatively early stage, but their terrestrial broadcasts were not received in Israel:
The frequencies at which the television signals are transmitted are quite high, several tens to several hundreds of MHz, and radio waves at such frequencies behave quite similarly to normal light - they do not easily pass through obstacles such as mountains and buildings. That's why we had to wait until satellite broadcasts of European TV stations started, then it was already possible to watch color TV.

The broadcast signals of our neighboring countries, on the other hand, can certainly be received through a normal antenna, because the distance to them is not great (especially if there are no disturbances on the way, such as TV broadcasts from Cyprus between us and a flat sea separating them). When they started broadcasting in color, any normal TV receiver, even without an expensive satellite dish, could receive a color broadcast.

Black and white televisions were quite common in Israel, but color televisions were still considered a distinct luxury product. Only the upper deciles could afford the luxury of color television.

The government was, therefore, in a very difficult dilemma. On the one hand, it is impossible to stop the broadcasts in color. It is physically impossible to prevent the broadcasts of foreign stations, unless we bombard the Jordanians and Cypriots, and with a hand on our hearts, it doesn't seem like they deserve such treatment and then we wouldn't either
Being exposed to masterpiece shows like Catch with Kerry Van Erick and the 700 Club.

Even worse, from the government's point of view of course: the Israel Broadcasting Authority bought programs from abroad, series like Dallas, Dynasty, Colombo, Cossack... Wow, I got a dose of nostalgia straight into my veins. All of these programs, recorded in the United States, were in color! This is how they were photographed.

Moreover, even Israeli television, our television, must broadcast in color from time to time. For example, the Eurovision Song Contest that took place here in '79 was filmed by the Broadcasting Authority and transmitted to all television stations in Europe - and according to the broadcasting regulations they were obliged to transmit a color broadcast. The Europeans are not interested in the fact that color TV is expensive in Israel.

But on the other hand, the government in Israel is always committed to some sort of equality between the weak and the powerful, preventing social gaps... I don't know how much of this is casual lip service that they don't really mean, and how much the government is really interested in preventing social gaps - but at least in appearance, this is what the government wanted to do.

The solution to the dilemma was extremely original, and to explain it we will have to understand a little more the principle of operation of the television and the way in which it interprets the signals it receives from the broadcasting station, and turns them into live images.

Let's talk now about normal televisions, the large and heavy receivers that we have known for years. LCD and plasma TVs are also able to receive the same broadcast signals, but their operating principle is completely different - I will talk about them later.

An unusual scientist

All televisions from the previous generation, before LCD and plasma, are of the type known as 'cathode ray tube'. The name 'cathode ray tube' sounds intimidating enough to make some listeners slightly vibrate their finger on the button that stops this podcast, but it's a lot less complicated than it sounds. After all, this is technology from a century ago, how complicated can it be, right?

A cathode ray tube is a large glass container empty of air, or filled with a vacuum, depending on which angle you like to look at such things. It was not easy, historically, to create a glass container empty of air. There is a combination of two difficult problems here: one, is the creation of the vacuum itself, and the meaning here is a high quality vacuum, as close to a perfect vacuum as you can get. The second problem is that when you try to create a vacuum in a glass container, you can't just close the lid after you've sucked out all the air - you have to close the container by massing the glass to seal the opening. Since it is, as mentioned, a combination of two difficult problems, there was a need for a scientist who had a successful combination of skills that would allow him to solve these problems.

That person was Heinrich Geisler. Geisler, who lived in Germany about one hundred and fifty years ago, was a very talented glassblower - it was a family business, and his father before him was a successful glassblower himself. Moreover, Geisler was not a bad physicist at all - this deadly combination of scientific knowledge and practical knowledge of working with glass. Fortunately for Giesler, he also lived at a time when his knowledge of working with glass was sorely needed.
Until the middle of the 19th century, or even a little before that, there were not many full-time scientists: there was no such profession, "scientist". Most of the people who engaged in scientific research were so-called "gentlemen": people from the middle-upper class, white-collar professionals, who usually engaged in research in their spare time. When more and more professional scientists began to appear, people who engaged in scientific research as a profession, more and more organized research laboratories also began to appear. And these laboratories needed equipment - for example thermometers, and barometers, and test tubes and many more such devices, many of which were made of glass.

Geisler established his workshop for the production of glass instruments not far from the University of Bonn, in Germany, and received many orders from scientists around the world. He earned a name for himself as a great expert, and won quite a few prestigious awards for the facilities he built.

One of the installations he built was a glass container into which Geisler inserted tiny metal electrodes. The tank was empty of air but Geisler left tiny amounts of special gases like neon inside. As soon as you applied an electrical voltage to the electrodes, the gas inside the tank would start to glow! It was something special, no one had seen anything like it before, of course, and Geisler's tubes were a real hit, especially as sophisticated toys: you would hold the glowing tube in your hand, and the gas inside would change its shape depending on the direction you held the tube and would make interesting shapes- Something like a sticklight like this, and I can testify from experience that soldiers in the army are fascinated by sticklights like four-year-old children.

Geisler's tubes also had more serious uses, and scientists began to investigate the phenomenon underlying this glow of the gases inside the tube. They quickly came to the conclusion that the electrodes in the vacuum tubes emitted a stream of particles, and further research revealed that these particles were electrons.

The bored student who invented television

Let's fast forward, fifty years, and return to television and the cathode ray tube. At one end of the receiver, sits an electrode that emits electrons - or in the more common and catchy name: an electron gun. This cannon, as the name suggests, fires a beam of electrons at a screen of phosphorous material that is applied to the other side of the receiver. When this ray hits the phosphor, it causes it to glow. We look at the phosphorescent material from the other side, outside the tube, so all we see is a glowing dot. If you think back, you will remember that when you turn off the television, sometimes the image disappears and for a split second there would only be a glowing spot in the center of the screen. did you remember So this point is exactly the point of impact of the electron beam in the phosphorescent material.

How does a single point become a real image on the screen? Here a certain weakness of our brain is manifested. I once read a quote from someone who said - 'I once believed that the human brain was the most important organ in the body - then I realized:
Who is the organ that tells me to think these things?...'.

Anyway, the brain is certainly an impressive calculating machine, but it has limitations. One such limitation is our ability to deal with rapidly changing images: if the image in front of our eyes changes too quickly, the brain is unable to notice the changes and creates an image for us that is essentially a summary of the changing images. For example, when you drive a car and look at the dotted lines on the road - at low speed they appear as single lines, but when we increase the speed they will mix with each other and appear as one wide line.

The same thing happens on television. The electron beam moves on the screen and draws stripes on it, one below the other for the entire height of the screen. When it reaches the bottom of the screen, the ray goes back up and starts drawing new lines. This process happens about sixty times a second, and it is so fast that for us all we see is a sum of stripes - we are unable to distinguish the real movement of the beam.

If we stopped here, all we would get on the screen was a solid white surface. To produce a real image on the screen, you need to tell the electron beam when to stop shining on the screen: note, the beam will continue its scanning movement to the width and height of the screen, but it will not always cause the phosphorescent material to light up. At the points where it will not shine, we will see black spots: this is how a black and white image is created.
The broadcast signals of the TV, the signals we receive through the antenna or the cable from the converter, in total tell the electron beam when to illuminate the screen and when to stop.

We will soon move on to the question of how a color image is created on the TV screen, but before that: how did they even arrive at such a transmission method? Why did you choose this method and not another?

Many people may be surprised to hear, but the television began as a mechanical device, not an electronic one. I mean, it was much closer, family-wise, to a car engine than to today's television. The mechanical television, or more accurately to say - the electromechanical - appeared for the first time around 1884, following the development of a device called 'Galgal Nifko', named after its inventor: Paul Gottlieb Nifko. Nipko was an engineering student, and on Christmas Eve, in 1883, he was alone at home. He probably didn't have much employment, and he sat and looked at an oil lamp. While he was looking at the flame flickering through the small holes in the lamp, he suddenly had the idea of ​​how to create a moving image, and this idea is a 'Nipko Wheel'.

A Nipko wheel is a metal wheel in which tiny holes are drilled. The holes are distributed on the wheel in a staggered manner: there is a hole close to the center of the wheel, followed by a further hole that is a little to the side of it, not quite above it, like a step, and so on, several dozens of small nozzles. Behind the wheel there is a lamp of some kind, say a neon lamp, whose lighting intensity can be changed, dimmed or increased.

The wheel was spinning at a very high speed. At any point in time while the wheel was turning, there was only one hole in front of the lamp, and this hole would outline, as it moved in front of the lamp, a streak of light. The intensity of the light strip obviously depended on the intensity of the lamp behind the wheel. We will remember that the holes were at increasing distances from the center of the wheel, so that the rotation of the wheel would create glowing stripes one after the other, like layers in a sandwich. By playing with the light intensity from the lamp it was possible to get a kind of very rough picture from this TV.

I said that the television was 'electromechanical', because even though the wheel was completely mechanical, there was a bit of electronics involved in the process of dimming the lights of the lamp, and of course receiving the signals from the outside that would tell the receiver when to dim and when to increase the intensity of the light, depending on the image you wanted to create on the screen. If this sounds familiar to you, then it is not by chance - it is exactly the same operating principle of today's televisions, more than one hundred and twenty years after they were produced, the engineering student thought of the idea. It took more than a century until someone came and thought of a better way to realize a television receiver - I'm referring here to LCD and plasma televisions - better than the idea of ​​Nipko the student.
Nifko himself, perhaps because he was a student and did not have the appropriate technical knowledge, never tried to build a Nifko wheel himself. He contented himself with registering a patent for the idea, and when the patent expired fifteen years later, anyone could already use it without paying the issuer, so he did not make a penny from his idea. As a gesture of respect, the first public television channel in Germany was named after him in 1935.

Television in wartime

The development of color television is a story in itself. The technology for color transmission and reception developed in several places in the world at the same time, but the United States was already at that time - the XNUMXs and XNUMXs - the most dominant power in the world, so it had the greatest impact on this development, which is why I focus on it.

Two large companies competed with each other for the right to be the company that will set the standard for color broadcasts in the United States and perhaps in the entire world. These two companies were RCA and CBS.

Already during World War II, the two companies began developing technology for color television broadcasts, but at that time in the United States there was a committee called the 'Wartime Production Committee', and this committee determined where the resources of the American economy would be directed - which mainly means military equipment needs. This committee prohibited CBS and RCA engineers from further developing this technology, apparently because it did not contribute too much to the American war effort. This committee also had quite a lot of spies from the Soviet Union, as it turned out many years later, and maybe they just wanted to abuse the Americans and prevent them from watching good television.

Not that adding color, by the way, ultimately contributed to the quality of the programs on television. As a man named Rod Serling said - 'It's hard to make a quality TV show when every fifteen minutes you're interrupted to show twelve bunnies dancing with toilet paper.'

In any case, the war is over, and the battle for color television has resumed in full force, with both companies seeking to convince the American government that their technology is superior and should be the national standard.

RCA's technology was cumbersome, expensive and of poor quality compared to what CBS presented, so the American government very quickly chose the CBS standard. But RCA, for all its problems, had one wild card up its sleeve: its method of color transmission was backwards compatible with black-and-white television broadcasts. I mean, if you already had a black and white TV at home, you could receive broadcasts in color - just without the color. The CBS method, on the other hand, required you to pick up a brand new TV! And I remind you that television was not such a cheap and common consumer product as it is today.

So even though CBS won the standard and started broadcasting in color, no manufacturer of television sets was willing to produce the appropriate sets because most of the public was not ready to give up the sets they had at home, which cost them a lot of money. The result was that by 1951, only a hundred or two hundred color television sets were in the public domain. CBS was forced to fold, announcing that it was ending its color broadcasts. Who was there to pick up the pieces was, of course, RCA. It worked together with other representatives of the American television industry to develop its technology, within a committee whose initials are NTSC. The new standard, called NTSC, was compatible with the old receivers: those who had a color receiver saw a color broadcast, and those who had an old generation receiver still saw television, only in black and white. How did they do it? They took the original transmission signals, of the black and white transmission, and 'dressed' the color transmission signals over them, so that now the same transmission had both the color information and the black and white information. The old generation TV did not know how to decode the broadcast signals in color, and simply ignored them - and only displayed the normal signals, in black and white. This method caught on properly.

And how did a color television receiver, which operated according to the RCA method, work? So. Let's recall for a second the black and white television: an electron gun in the back, which shoots an electron beam at a phosphorescent substance that is smeared on the screen. The beam moves across the screen and in this way creates an image.
In a color television receiver, instead of a single electron gun there are three guns. And instead of one phosphorescent material that is applied to the bulb, there are three such materials - one that produces red light, one blue and one green. When you want to draw a red picture, you shoot an electron beam from the appropriate cannon at the red phosphorescent material, and surprise surprise - we got a red dot on the screen. Of course, a combination of all three colors makes it possible to reach many shades of intermediate colors such as orange, yellow, brown, etc.

The Israeli head

If so, we will return to the Israeli government and its fight against the demon of the threat of color television broadcasts. The solution to the problem of the mismatch between those who have color in their living room and those who are still stuck with the old receivers, the way to prevent color transmission, was to throw out the signals that told the television how to transmit in color, and leave only the signals that explain how to see in black and white. To throw away, the intention is to 'delete' these signals - the device that performed the deletion operation was given the honorific name of 'deletion'.

But there was one problem. It was impossible to completely erase the color signals. They were terribly stubborn, and were worn really hard on the letter of the black and white - to erase them completely you would destroy the black and white image as well, and they didn't want to do that. So delete what was possible, which was part of the transmission called 'synchronization signal'. The sync signal is the signal that allows the TV receiver to decode the color signals of the TV broadcast. As the name suggests, this signal allows the receiver to synchronize, in other words, to lock onto the color signals and separate them from the black-and-white broadcast. So deleting the sync signal from the TV broadcast prevented the receiver from locking onto the color broadcast, and this was enough to mean that viewers could only enjoy black-and-white broadcasts.

But the Israeli head cannot be erased, and as we know, they did not do it with a finger. According to the website 'Wikipedia' in Hebrew, the person who found the way to overcome the erasure of the color signals from the broadcasts was an electronics engineer named Molly Aden, who also became in many days the CEO of the Intel development center in Haifa, according to certain instructions given to him by his manager at the company 'Metz Electronics' Yitzhak Vogel.
Molly's solution was to build a device that itself produces the synchronization signal that the Broadcasting Authority did not transmit, a device that was assembled inside each television receiver by itself, thereby eliminating the need to receive this signal from the outside.

This facility actually canceled the erasure of the color signals, hence the name 'anti-erasure'. The combination of the broadcasts from the Broadcasting Authority and the color signals of the anti-erasure inside the TV receiver itself, returned the color image to the screen. The 'anti-erasure' was not without its problems. Since the synchronization signal was produced within the television set itself and not by the broadcasting authority, it was not always truly synchronized with the color broadcast. When this happened, the receiver would lock on the colored signals but with a small deviation, which would make the color fake and not match reality, and you had to adjust the anti-aliasing manually every so often, to produce a good color. And it was also quite expensive - up to 4000 pounds, which is almost ten percent of the price of a new color television in those days. But that's what it was, everyone who could afford it bought the anti-delete - and it worked beautifully.

In the end, the Israeli government had no choice but to realize that it cannot fight this stupid war, and the 180 million pounds a year it invests to erase the color from television broadcasts goes down the drain because everyone watches color broadcasts anyway. Therefore, starting in 1981, the Broadcasting Authority began to gradually switch to full color broadcasts, and there was no longer a need for such an anti-deletion.

carrot juice

I previously promised a few words about more advanced television receivers, and since I am not trying to be elected to the Knesset I will even keep my promise. If normal TVs started from something that was very similar to a car engine, LCD TVs started from a segment.
Yes, a carrot. This thing that Eliezer is attracted to and that the doctors tell us is good for the eyes.

LCD is an English acronym for liquid crystal display. A liquid crystal is a substance that is halfway between being a real liquid and a crystal - like glass or a crystal, for example. The one who discovered this feature was a plant researcher named Friedrich Reinzinger, about one hundred and twenty years ago. I suddenly noticed that this whole chapter is full of German scientists. interesting. Anyway, Friedrich discovered that a certain substance he produced from a sector behaves in a strange way when heated. At a certain temperature it takes on a white color, and when the temperature rises it suddenly becomes transparent. What actually happens is that the crystalline material extracted from the carrot is able to block the light or allow it to pass through without interruption depending on the temperature.

LCD TV works the same as the carrot, only it is less good for the eyes. On the other hand, as one of the Marx brothers said, the television contributed a lot to my education: every time someone turns on the television, I go to another room and open a good book.

In an LCD TV, there are masses of liquid crystals that are powered by an electrical voltage. When there is no electrical voltage applied to the crystal, it allows light to pass from the lamp behind the screen, to the viewer's eye. When there is an electrical voltage on it, the crystal does not allow the passage of light, and the small dot on the screen appears dark. If you change the electrical voltage fast enough on a large amount of crystals, you get a moving image on the screen.

From the above description, it is clear that an LCD TV works in a completely different way than a cathode ray tube TV. But what is interesting is that the signals coming from the broadcasting station still remained exactly the same. Here too, as in the transition from black and white to color television, they did not want to change all the equipment of the broadcasting station just because some people decided to buy an LCD television. So the signals are the same signals, suitable for the technology of one hundred and fifty years ago, only they are interpreted inside the receiver to match them with carrot juice, sorry, for the liquid crystals of the LCD television.

Plasma TVs, which are also very common these days, work on a completely different principle. The screen of a plasma TV is made of hundreds of thousands of small fluorescent lamps - maybe not exactly fluorescent lamps like we are used to seeing on the ceiling, but something really, really similar. These lamps, which are in principle descendants of the lamps built by the well-known Heinrich Geisler, create an entire surface of tiny points of light.

Since each lamp on the surface can be activated separately by electric voltage, it is possible to put many such lamps next to each other, without any connection between each other, thus creating huge television screens - which is the hallmark of plasma televisions.

Undoubtedly, the TV viewing experience has changed beyond recognition, which is not necessarily true of the content. Today, watching television is full of beatings, violence and foul language - and it's just a matter of who will hold the remote.

So much for the sad and funny story of the Anti-Machikon.

History, as always, repeats itself. Thirty years have passed, and here the record companies are trying to fight against file sharing, which is like waving a barbecue carton against a tornado. There is no doubt that their intention, to protect the copyrights and their profits, is a good and correct goal - just like the social justice aspirations of the Israeli government - but all the signs indicate that this fight will also end in a clear knockout, like the knockout that a tiny electronic device inside the television, the anti-copying, gave to the government Israel.

מקור

This article is taken from the program script 'Making history!', A bi-weekly podcast about the history of science and technology.