How does it work? - Radio

How does it work? - Radio

This animation demonstrates how radios work.

Technology

Keywords

radio, radio wave, radio broadcast, radio receiver, radio station, relay station, speaker, antenna, tuner, amplifier, transformer, demodulator, FM, AM, amplitude modulation, frequency modulated signal, frequency, electromagnetic, electric current, physics, technology

Related items

Scenes

  • - Amplitude modulation. These signals can travel through thousands of kilometers as the upper layer of the atmosphere and the ground reflect them multiple times. FM broadcasting covers a shorter distance than AM broadcasting; however, they are subject to less interference. For this reason, FM broadcasting tends to be less noisy.
  • - Frequency modulation. Since these signals travel in a linear way, they can only be used for short distance broadcasting. The receiver therefore always have to "see" the transmitter. They are, however, subject to less interference.

During modulation, input signals are combined with electrically induced radio waves, as transmission is only effective if the frequency of the carrier wave is much higher than that of the input signal.
When the amplitude of the carrier wave is changed in accordance with the intensity of the signal, the process is called amplitude modulation (AM). When the frequency of the signal is changed according to the signal's intensity, the process is called frequency modulation (FM).

AM signals are used for long-distance broadcasting within the low (1,000–2,000 m or 3281–6562 ft), medium (187–577 m or 613.5–1,893 ft) and high frequency (10–100 m or 32.81–328.1 ft) radio bands.
These waves can travel thousands of kilometers as the upper layer of the atmosphere and the ground reflect them multiple times. AM signals are, however, subject to static and interference. For this reason, AM broadcasting tends to be noisier.
FM signals are used for high fidelity broadcasting. These signals, however, only travel in a straight line, which means they can only be used for short-distance broadcasting, and the receiver always has to "see" the transmitter.

Amplitude modulated (AM) signal

Frequency modulated (FM) signal

  • - Amplitude modulation. These signals can travel through thousands of kilometers as the upper layer of the atmosphere and the ground reflect them multiple times. FM broadcasting covers a shorter distance than AM broadcasting; however, they are subject to less interference. For this reason, FM broadcasting tends to be less noisy.
  • - Frequency modulation. Since these signals travel in a linear way, they can only be used for short distance broadcasting. The receiver therefore always have to "see" the transmitter. They are, however, subject to less interference.

Narration

Sound is first converted into electric signals with a microphone. After modulation and amplification, signals are sent through the air as electromagnetic radio waves using antennas.

During modulation, input signals are combined with electrically induced radio waves, as transmission is only effective if the frequency of the carrier wave is much higher than that of the input signal.
When the amplitude of the carrier wave is changed in accordance with the intensity of the signal, the process is called amplitude modulation, or AM. When the frequency of the signal is changed according to the intensity of the signal, the process is called frequency modulation, or FM.

AM signals are used for long-distance broadcasting. These waves can travel thousands of kilometers as the upper layer of the atmosphere and the ground reflect them multiple times. AM signals are subject to static and interference, however. That is why AM broadcasting tends to be noisier.

The main parts of the radio are the tuner (located in the integrated circuit), the demodulator, the amplifier and the speaker. The tuner is used to search for the frequency of the station we wish to listen to.
The demodulator, also called the detector, demodulates the radio signal selected by the tuner by separating it from the carrier wave. The wave is then amplified in the amplifier and transmitted to the speaker. Here, electric signals cause the membrane in the speaker to vibrate and create sound waves.

Related items

Phonograph and gramophone

Edison´s invention records and plays sound from a cylinder, while Berliner´s apparatus uses a disc.

Telegraph (Samuel F. B. Morse)

The American inventor presented his invention revolutionizing telecommunication at New York University in 1837.

DC motor

DC motors consist of a permanent magnet and a coil within the magnet, with electric current flowing in it.

How does it work? - Cell phone

This animation demonstrates how cell phones work.

How does it work? - Computer networks

The Internet allows us to send data quickly to large distances.

How does it work? - CRT television

This animation demonstrates how a CRT television works.

How does it work? - Hair dryer

This animation demonstrates the structure and operation of hair dryers.

How does it work? - Loudspeaker

In loudspeakers sound waves are generated by electromagnetic induction.

How does it work? - Optical disc drives

This animation demonstrates the structure and operation of different types of optical disc drives.

How does it work? - Record player

This animation demonstrates the mechanism and operation of record players.

How does it work? - Washing machine

This animation demonstrates how a washing machine works.

Lute and hurdy gurdy

The earliest version of the lute appeared in ancient Mesopotamia.

Piano

The piano is one of the most popular instruments in the world. It is a chordophone which produces sounds mechanically.

Telephone (Alexander Graham Bell)

The device that transmits human voice as electrical signals was invented by Bell in 1876.

The development of television sets

Television, invented in the early 20th century, became one of the basic forms of entertainment.

Torsion balances

A force can be measured by measuring the twisting of the torsion wire in a torsion balance.

Added to your cart.