For reasons of kinescope authors (and television) could not appear before the first bulb. Each kinescope (and TV) is constructed according to the scheme: available cathode voltage heated, for example, 6.3 V, and the anode is coated with a phosphor. If properly manage the movement of electrons and their density, manages to form a spot on the screen of differing brightness, which is considered to have an image. In the case of a color television only difference is in the number of cathodes. Three cathodes beating clearly in own phosphor (in the form of triads collected rods and dots). Otherwise, the image becomes slightly different color, float, will be other negative effects.
Pro TV and TV
Even before the experiments with the radio signal is transmitted through the wires, the first mechanical television sets used for transmission over a distance of the photos in printing. When undeveloped due to get a photo of the ocean (which this was done by Marconi) sounded very tempting. Suppose Eugene Sandow holds own funds first bodybuilding competition, and only the newspaper pestreyut fresh photos transmitted mechanical television in the United States.
Eugene Sandow was born in Prussia for a dozen years before the creation of the cathode tube - TV ancestor, actively developed the first technique weights training. In 1901 he held the first competition where the majority of participants engaged in by the author's programs. There are grounds for believing that a person referred to Edgar Burroughs wrote off an English lord, born in the jungle - as a result of the rebellion on the ship - which the world learned today under the name of Tarzan. In particular, Sandow practiced fighting with a lion, clad in mittens and wearing a muzzle. Finally, we admire today on Sandow, looking at the TV screen class competition Mr. Olympia. You thought whose statuette is awarded to the winner?
Sandow died in 58 years in unclear circumstances. Presumably, he ruptured when one arm pulled out of the ditch cars, and his wife buried her husband in a grave without a headstone.
For transmission over the ocean picture needed to make the device, reading the image. Mechanical TV set up on the basis of Nipkow disk (the year of the invention - 1884). Opaque wheel slotted holes extending at equal angular distances and at an equal pitch toward the center. It turns helix with a single coil. For example, the first opening is located at the periphery of the second bit closer and t. D. to the center of the television. Behind arranged projecting sensitive elements. We will not go into the basic elements of the first TVs, just say it through the hole on the projected screen at once the whole line.
The more fit holes, the greater the exerted TV vertical resolution and the horizontal determined by the number of elements (bulbs). It was difficult to achieve high speed, the inertia of the eye requires the construction of an image 24 times a second. For example, a typical disk Nipkow TV showed 30 lines, then needed a second to make a 24 x 30 times that of old times turned complicated. Cinematography limp, where the diaphragm urged to do these 24 oscillations per second. Acceptable quality for printing in newspapers, even a simple picture, made with the help of the first mechanical TV, could not be done. Already by 1909 instant scanning for monochrome image appeared satisfied.
Black and white television
In this light, it becomes clear why the question of who invented the television, will cause difficulties for professionals. So many people had a hand in that it is difficult to understand whose merit more. The first black-and-white kinescope was ready in 1879, 5 years before the invention of Nipkow disk. In particular, Crooks found that beams deflected by the magnetic field causes the light to the phosphor.
On the basis of the described invented cathode gun. Initially, vertical receive a mirror, then I began to use Nipkow disk. Actually, the scanning device (1909) for photos closely concerned Braun tube (with a mirror). As you can see, the area rapidly developing technology. The first television cathode ray tube invented in 1922 year, characterized by a heated cathode, which greatly improved the quality of the image. Sandow invention survived for three years, it belongs to a man with a straightforward name of John Johnson, a US citizen, but of Swedish origin. Home appliances - TVs are no exception - most obliged to the birth of America, where in ancient times (the first half of the 20th century) even published a magazine, which published news and innovative use of traditional methods technology.
The first commercial television cathode ray tube came out in 1934 in Germany. However, the TV in its current form came into being thanks to the two Russian compatriots. A talented engineer Vladimir Zworykin was appointed chief of the electronics laboratory of David Sarnow. In 1929, Zworykin invents the television kinescope in its final form, a couple of years later - ike (transmitting tube). Thus laid the foundations for the transmission of images at a distance. It remains to put on a carrier, and aired on the will to the four winds, and televisions. Antennas and Radio invented in the late 19th century, what made efforts Popov, Marconi and other scientists.
What is included in a typical TV
To overcome the information broadcast, it was transformed into a form that is easy to move in space. Quickly realized that the sound frequency is difficult to reject, as they decay, on the contrary, it is extremely fast. We found a solution: to lay the information in the high-frequency signal, called carrier. Modified amplitude, frequency or phase (the last two process engineers tend to be regarded as something akin). As a result, required to transmit the image and sound. For each type of information set up their own carrier. Suppose an image transmitted amplitude modulation, audio - frequency.
Today, many ways to encrypt information. The carrier signal from the encoded digital ones and zeros. Content to become available, it is required to possess the key. So made protection from unauthorized access. What happens inside the TV:
- The signal received via the antenna amplifier on the input resonant circuits, filters for performing channels. Typically, circuit configured to skip a single source of information, reducing the amount of interference significantly.
- Then the signal is amplified. Cascade assumes no clearly allocated bandwidth, another setting would obviously complicated.
- Extract information from uncomfortable high frequency in a mixer frequency is reduced to a standard. For example, the radio is 465 kHz. The local oscillator generates oscillations from which is subtracted the signal came. Of course, the frequency adjusts to the channel search software handle (channel selector in the simplest case).
- To the local oscillator is not lost, there is a TV in the automatic adjustment circuit frequency, it allows you to extract the information as fully as possible.
- After the transfer procedure occurs at a stable frequency reverse process to modulation, which is called detection. Permissible amplitude detector called a demodulator. The difference is so subtle that only interested in professionals.
- Chronology ends a low frequency amplifier, generates a signal for the cathode ray tube. Frame and line scanning laid here, there are circuits for their isolation from the overall hash. Commonly used a relatively large level signals.
Later we will tell, when the first color TV than LCD TVs are good, why you should not confuse the concept of plasma televisions and laser TVs. We hope our efforts will not go to waste.