What waves does the TV pick up? What waves does it pick up?

2. The principle of plumbing.
3. Natural form of inorganic substances.
4. Universal form of energy.
5. Capacity for storing electricity.
6. Emitter of infrared rays.
7. What waves does the TV catch.
8. What rays reflects the surface of the lemon.
9. What should be the human economy.

Answer the questions just number!

1) The main source of protein food in the future.
2) What keeps the ship afloat.
3) The principle of plumbing.
4) Heavy, shiny, hard, plastic...
5) (Grandmother) of all engines.
6) A universal form of energy.
7) Does sound propagate in space.
8) Emitter of infrared rays.
9) What waves does the TV catch.
10) What rays reflects the surface of the lemon.
11) What should be the human economy.

please help answer the questions: 1-artificial varieties of animals 2-way of maintaining

the fertility of the fields 3- device to improve the microclimate 4- main consumer in artificial ecosystems 5- the main source of protein food in the future 6- what helps to lift weight 7- the main part of land transport 8- washing property of water 9- what keeps a ship afloat 10- principle of plumbing 11- what keeps a person warm in warm clothes 12- airborne device 13- finely ground stone powder 14- natural form of inorganic substances 15- heavy, shiny, hard plastic... 16- property that the blacksmith uses 17- raw material for gasoline production 18- "grandmother" of all engines 19- universal form of energy 20- capacity for storing electricity 21- does sound travel in space 22- infrared ray emitter 23- what waves does the tv pick up 24- what rays reflect the surface of the lemon 25- main part of a computer 26- objects revolving around the earth 27- what should be the human economy

The great scientist Isaac Newton wrote: “I don’t know about others, but I feel like a child who wanders all day at the water’s edge, finding either a shell or

a pebble polished by a wave, while a vast ocean of truth stretches before us, boundless, unexplored.” How do you explain these words?

Complete the sentences with. They talk about how you hear.

When sound waves appear, the auricle, as it were, collects them and directs them to ........... (Insert a missing word). Passing through the ear canal and hitting the eardrum, sounds cause it ............... (Insert missing word). The vibrations are amplified and are transmitted through the sound ossicles (anvil, ...............) to the cochlea. The snail is filled with fluid, and its inner..............(Insert missing word) is covered with cells with tiny................(Insert missing word) . Each hair is a "string", which by .......... (Insert the missing word) transmits its sound to the brain. The brain collects all the sounds, trying to understand what is heard.
Help me please! This is the world around the ear

An analog television signal is several megahertz wide, so the long, medium, and short wave bands are too narrow for it. To transmit such signals, at least ultrashort waves are used. This situation has not changed with the transition to digital television.

Instruction

The wavelength ranges allocated for television broadcasting vary from country to country. In Russia, for analogue broadcasting on meter waves, the D standard has been adopted, which provides for 12 channels. The first of these corresponds to a frequency of 49.75 MHz for transmitting an image signal and 56.25 MHz for transmitting a sound signal. In the last of them, the image and sound are transmitted, respectively, at frequencies of 223.25 and 229.75 MHz. Transmissions on decimeter waves used to be conducted not in all cities, but today - in almost every one. Channel frequencies in this range are set by the K standard. On the first of them, number 21, frequencies of 471.25 and 477.75 MHz are provided for image and sound signals. The last channel of the range was at first 41 (631.25 and 637.75 MHz), then 60 (783.25 and 789.75 MHz), and today this is channel number 69 (855.25 and 861.75 MHz). The modulation of the image signal is amplitude, the sound is frequency. An attentive reader will consider that in all cases the difference between the frequencies for transmitting image and sound is 6.5 MHz. In other countries this difference may be different, for example 5.5 MHz (standards B and G).

There are large gaps between channels 5 and 6, as well as 12 and 21. It is impossible to arrange television broadcasting on the air on frequencies that fall into these intervals - this can interfere with radio broadcasting and other types of communication. But they can broadcast over cable, which is often practiced today. At first, TVs were unable to work in these ranges - set-top boxes were required. Now, almost all TVs can receive these channels, which have received numbers from S1 to S40, on their own. The frequency differences for the transmission of image and sound signals on these channels also comply with the standards adopted in the country.

Digital television broadcasting is carried out at frequencies within the existing decimeter range, so existing antennas can be used. Only between the antenna and the TV you need to place a prefix-decoder, or use a TV with a built-in decoder. But thanks to compression in digital broadcasting, it is possible to introduce so-called multiplexes, when several television channels broadcast on one frequency channel. In the DVB-T2 standard, compression is even more efficient than in DVB-T. Cable broadcasting uses DVB-C and DVB-C2 standards.

Satellite television uses frequency ranges corresponding to units and tens of gigahertz. Previously, it was also analog, but frequency modulation was also used to transmit image signals. Now satellite broadcasting is carried out in the same ranges, but using digital standards, in particular, DVB-S and DVB-S2.

Radio waves with frequencies ranging from 3 kHz to 300 GHz belong to the electromagnetic spectrum. Other facts about radio waves are presented in this article.
Wave transmission!
A significant discovery in the field of communication transmission, radio waves were discovered in 1867 by the Scottish physicist James Maxwell.
Have you ever noticed that most of the devices we use in our lives are based on the concept of transmitting data via radio waves.

A television antenna receives electromagnetic waves from a television station and in turn transmits various channels. Microwave or telephone, almost all of our devices require radio waves to operate or transmit data. Radio waves are mainly used to transmit information in space. Their main function is to transmit data through modulation. They have an advantage over many other types of signals due to the fact that their speed is equal to the speed of light when moving in a vacuum. High transfer rates make the transfer process very efficient.
How do radio waves work?
Telecommunications in a wireless environment mainly use electromagnetic signals. The carrier signal is one such electromagnetic signal used to convey information in space. The carrier signal is modulated to carry different types of data. AM and FM are examples of such modulations used for broadcasting radio waves. Let's take an example to understand this concept better. A radio antenna is required to receive signals from AM and FM stations. This makes the radio capable of picking up a range of signals. The radio tuner is then used to tune in to the required frequency. The radio receiver converts the received signals into sound for the listener.

Some facts about radio waves.
◾ Radio wave length refers to the distance from one peak to another in the electric field of the wave. It ranges from 1 mm to 100 kilometers.

◾ The frequency of radio waves is how close these waves are. The frequency of these wave types range from 3 kHz to 300 GHz. The amplitude determines the height of the radio waves.

◾ The length and frequency of radio waves are inversely proportional.

◾ The misconception that radio waves are sound waves, they are electromagnetic waves.

◾ Radio waves can travel long distances with minimal energy consumption.

◾ A radio wave travels from the Earth to the Sun in 8 minutes.

◾ FM has higher sound quality than AM.

◾ AM is cheaper than FM and can be transmitted over long distances without modification.

◾ A radio wave is almost 100,000 times longer than visible light.

◾ Radio waves can travel at different frequencies.

◾ Radio waves can be generated naturally through the use of astronomical bodies or lightning.

◾ The use of radio waves is subject to various laws. This is done in order to avoid mutual interference between different frequencies.

◾ Radio waves are used in telescopes, radios, x-ray machines, cell phones, and radio controlled toys.

◾ Astronauts use radio waves to communicate with the earth.

◾ Airplanes and large ships use a radio compass to navigate.

◾ Antennas and telescopes also use radio waves to transmit and receive data.

An analog television signal is several megahertz wide, so the long, medium, and short wave bands are too narrow for it. To transmit such signals, at least ultrashort waves are used. This situation has not changed with the transition to digital television.

Instruction

The wavelength ranges allocated for television broadcasting vary from country to country. In Russia, for analogue broadcasting on meter waves, the D standard has been adopted, which provides for 12 channels. The first of these corresponds to a frequency of 49.75 MHz for transmitting an image signal and 56.25 MHz for transmitting a sound signal. In the last of them, the image and sound are transmitted, respectively, at frequencies of 223.25 and 229.75 MHz. Transmissions on decimeter waves used to be conducted not in all cities, but today - in almost every one. Channel frequencies in this range are set by the K standard. On the first of them, number 21, frequencies of 471.25 and 477.75 MHz are provided for image and sound signals. The last channel of the range was at first 41 (631.25 and 637.75 MHz), then 60 (783.25 and 789.75 MHz), and today this is channel number 69 (855.25 and 861.75 MHz). The modulation of the image signal is amplitude, the sound is frequency. An attentive reader will consider that in all cases the difference between the frequencies for transmitting image and sound is 6.5 MHz. In other countries this difference may be different, for example 5.5 MHz (standards B and G).

There are large gaps between channels 5 and 6, as well as 12 and 21. It is impossible to arrange television broadcasting on the air on frequencies that fall into these intervals - this can interfere with radio broadcasting and other types of communication. But they can broadcast over cable, which is often practiced today. At first, TVs were unable to work in these ranges - set-top boxes were required. Now, almost all TVs can receive these channels, which have received numbers from S1 to S40, on their own. The frequency differences for the transmission of image and sound signals on these channels also comply with the standards adopted in the country.

Digital television broadcasting is carried out at frequencies within the existing decimeter range, so existing antennas can be used. Only between the antenna and the TV you need to place a prefix-decoder, or use a TV with a built-in decoder. But thanks to compression in digital broadcasting, it is possible to introduce so-called multiplexes, when several television channels broadcast on one frequency channel. In the DVB-T2 standard, compression is even more efficient than in DVB-T. Cable broadcasting uses DVB-C and DVB-C2 standards.

Satellite television uses frequency ranges corresponding to units and tens of gigahertz. Previously, it was also analog, but frequency modulation was also used to transmit image signals. Now satellite broadcasting is carried out in the same ranges, but using digital standards, in particular, DVB-S and DVB-S2.

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I think everyone turned the radio knob, switching between "VHF", "DV", "SV" and heard hissing from the speakers.
But apart from deciphering the abbreviations, not everyone understands what is hidden behind these letters.
Let's take a closer look at the theory of radio waves.

Radio wave

Wavelength (λ) is the distance between adjacent wave crests.
Amplitude (a) - the maximum deviation from the average value during oscillatory motion.
Period (T) - the time of one complete oscillatory movement
Frequency(v) - number of complete cycles per second

There is a formula that allows you to determine the wavelength by frequency:

Where: wavelength (m) is equal to the ratio of the speed of light (km / h) to the frequency (kHz)

"VHF", "DV", "SV"

Ultra long waves- v = 3-30 kHz (λ = 10-100 km).
They tend to penetrate deep into the water column up to 20 m and, therefore, are used to communicate with submarines, moreover, the boat does not have to float to this depth, it is enough to throw out the radio buoy to this level.
These waves can propagate up to the envelope of the earth, the distance between the earth's surface and the ionosphere, represents for them a "waveguide" through which they propagate unhindered.

Long waves(LW) v = 150-450 kHz (λ = 2000-670 m).


This type of radio wave has the ability to bend around obstacles and is used for communication over long distances. It also has a weak penetrating power, so if you don't have an external antenna, you are unlikely to be able to pick up any radio station.

medium waves(MW) v = 500-1600 kHz (λ = 600-190 m).


These radio waves are well reflected from the ionosphere, located at a distance of 100-450 km above the earth's surface. The peculiarity of these waves is that in the daytime they are absorbed by the ionosphere and the reflection effect does not occur. This effect is used practically for communication, usually for several hundred kilometers at night.

short waves(HF) v= 3-30 MHz (λ = 100-10 m).

Like medium waves, they are well reflected from the ionosphere, but unlike them, regardless of the time of day. They can propagate over long distances (several thousand km) due to reflections from the ionosphere and the earth's surface, such propagation is called jump. High power transmitters are not required for this.

Ultra Short Waves(VHF) v = 30 MHz - 300 MHz (λ = 10-1 m).


These waves can go around obstacles several meters in size, and also have good penetrating power. Due to such properties, this range is widely used for radio broadcasts. The disadvantage is their relatively rapid attenuation when encountering obstacles.
There is a formula that allows you to calculate the communication range in the VHF band:

So, for example, when broadcasting from the Ostankino TV tower 500 m high to a receiving antenna 10 m high, the communication range under the condition of direct visibility will be about 100 km.

High frequencies (HF-centimeter range) v = 300 MHz - 3 GHz (λ = 1-0.1 m).
They do not go around obstacles and have good penetrating ability. Used in cellular networks and wi-fi networks.
Another interesting feature of the waves of this range is that water molecules are able to absorb their energy to the maximum and convert it into heat. This effect is used in microwave ovens.
As you can see, wi-fi equipment and microwave ovens operate in the same range and can affect water, so you should not sleep in an embrace with a wi-fi router for a long time.

Extremely high frequencies (EHF-millimeter range) v = 3 GHz - 30 GHz (λ = 0.1-0.01 m).
Reflected by almost all obstacles, freely penetrate the ionosphere. Due to their properties, they are used in space communications.

AM-FM

Often, receiving devices have am-fm switch positions, what is it:

AM- amplitude modulation

This is a change in the amplitude of the carrier frequency under the action of an encoding waveform, for example, a voice from a microphone.
AM is the first type of modulation invented by man. Among the shortcomings, like any analog type of modulation, it has low noise immunity.

FM- frequency modulation


This is a change in the carrier frequency under the influence of the coding wave.
Although this is also an analog type of modulation, it has a higher noise immunity than AM and is therefore widely used in the soundtrack of TV broadcasts and VHF broadcasts.

In fact, the described modulation types have subspecies, but their description is not included in the material of this article.

More terms

Interference- as a result of reflections of waves from various obstacles, the waves add up. In the case of addition in the same phases, the amplitude of the initial wave may increase, in the case of addition in opposite phases, the amplitude may decrease down to zero.
This phenomenon is most pronounced when receiving VHF FM and TV signals.


Therefore, for example, indoors, the quality of reception on an indoor TV antenna strongly “floats”.

Diffraction- a phenomenon that occurs when a radio wave encounters obstacles, as a result of which the wave can change amplitude, phase and direction.
This phenomenon explains the connection on SW and SW through the ionosphere, when the wave is reflected from various inhomogeneities and charged particles and thereby changes the direction of propagation.
The same phenomenon explains the ability of radio waves to propagate without direct visibility, bending around the earth's surface. To do this, the wavelength must be commensurate with the obstacle.

PS:

I hope that the information I have described will be useful and will bring some understanding on this topic.