A television (TV) or mirror is an electronic device that receives television signals and converts them into images and sounds.
Braun HF 1 TV, released in Germany in 1959.
Television (tele… and Latin viso – I look) is a radio-electronic device designed to receive, amplify and convert electrical signals (telesignals) of television broadcasts transmitted from a television studio into images and sounds. There are colored and plain, stationary and portable types.
The electrical signals distributed from the television center are caught by the receiving antenna and transmitted to the television through the cable. In this case, the vibrations are amplified, separated into image and sound signals, and then transmitted to the kinescope and radio speaker. A television raster is created on the kinescope screen by means of generators (line spreading and frame spreading generators). On a white TV, picture signals appear as black and light elements.
Depending on the number of programs that can be received, televisions have one, three, five, twelve, thirty-one and other channels. Television channels operating in the meter wave range are used for reception. To receive programs in the decimeter range, a separate device – a converter – is placed on televisions. It receives a decimeter signal and adapts its frequency to the frequency of the first, second or other television channel.
The structure of televisions is standardized. Their simplified scheme consists of a channel switching unit, video and audio channels, synchronization channels, a spreading unit and a power supply unit. TV studios broadcast several programs at the same time. To see what they need, a tuning block is used on the TV. This unit is connected to a high frequency amplifier. Since video and sound signals are transmitted at different frequencies, after amplification of these signals, high-frequency vibrations are separated and go on different independent channels. Sound signal vibrations fall on the sound block. In the image unit, the detector extracts image signals from high-frequency vibrations.
The structure of color televisions is more complex, they differ from standard televisions with a color channel block and a color kinescope. The color television system will have 3 channels. The monochrome constituents red (Q), blue (K) and cyan (3) are mixed in a color mixer and then passed to the transmitter modulator. The vibrations are again divided into 3 frequency channels (Q, K and 3) in the receiver and passed to the color kinescope.
According to quality parameters, screen size and ease of use, televisions are divided into 4 classes: I – III class – stationary TVs, IV class – portable (portable) TVs. Usually, the TV is made of separate structural blocks, widely used printed assembly. Semiconductor devices, integrated boards, and transistors are mainly used in televisions. Televisions with flat screens and electroluminescent, very large and small screens have been created.