Radio

radio communicationradio communicationswirelessradio transmissionterrestrial radioradiosradio channelradiocommunicationradio technologyradio commentator
Radio is the technology of using radio waves to carry information, such as sound and images, by systematically modulating properties of electromagnetic energy waves transmitted through space, such as their amplitude, frequency, phase, or pulse width.wikipedia
5,826 Related Articles

Amplitude modulation

AMamplitude modulatedamplitude-modulated
Radio systems need a transmitter to modulate (change) some property of the energy produced to impress a signal on it, for example using amplitude modulation or angle modulation (which can be frequency modulation or phase modulation).
Amplitude modulation (AM) is a modulation technique used in electronic communication, most commonly for transmitting information via a radio carrier wave.

Transmitter

radio transmittertransmittersradio transmitters
Radio systems need a transmitter to modulate (change) some property of the energy produced to impress a signal on it, for example using amplitude modulation or angle modulation (which can be frequency modulation or phase modulation). A radio communication system requires a transmitter and a receiver, each having an antenna and appropriate terminal equipment such as a microphone at the transmitter and a loudspeaker at the receiver in the case of a voice-communication system.
Transmitters are necessary component parts of all electronic devices that communicate by radio, such as radio and television broadcasting stations, cell phones, walkie-talkies, wireless computer networks, Bluetooth enabled devices, garage door openers, two-way radios in aircraft, ships, spacecraft, radar sets and navigational beacons.

Radio wave

radio wavesradioradio signal
Radio is the technology of using radio waves to carry information, such as sound and images, by systematically modulating properties of electromagnetic energy waves transmitted through space, such as their amplitude, frequency, phase, or pulse width.
Radio waves are very widely used in modern technology for fixed and mobile radio communication, broadcasting, radar and other navigation systems, communications satellites, wireless computer networks and many other applications.

Antenna (radio)

antennaantennasradio antenna
The electromagnetic wave is intercepted by a tuned receiving antenna. A radio receiver receives its input from an antenna and converts it into a form that is usable for the consumer, such as sound, pictures, digital data, measurement values, navigational positions, etc. Radio frequencies occupy the range from a 30 Hz to 300 GHz, although commercially important uses of radio use only a small part of this spectrum. The transmitter sends the modulated electrical energy to a tuned resonant antenna; this structure converts the rapidly changing alternating current into an electromagnetic wave that can move through free space (sometimes with a particular polarization).
Antennas are essential components of all radio equipment.

Microphone

microphonescondenser microphonedynamic microphone
A radio communication system requires a transmitter and a receiver, each having an antenna and appropriate terminal equipment such as a microphone at the transmitter and a loudspeaker at the receiver in the case of a voice-communication system.
Microphones are used in many applications such as telephones, hearing aids, public address systems for concert halls and public events, motion picture production, live and recorded audio engineering, sound recording, two-way radios, megaphones, radio and television broadcasting, and in computers for recording voice, speech recognition, VoIP, and for non-acoustic purposes such as ultrasonic sensors or knock sensors.

Frequency

frequenciesperiodperiodic
Radio is the technology of using radio waves to carry information, such as sound and images, by systematically modulating properties of electromagnetic energy waves transmitted through space, such as their amplitude, frequency, phase, or pulse width.
In physics and engineering disciplines, such as optics, acoustics, and radio, frequency is usually denoted by a Latin letter f or by the Greek letter \nu or ν (nu) (see e.g. Planck's formula).

Electrical resonance

resonanceresonateResonant
The electrical resonance of tuned circuits in radios allow individual frequencies to be selected.
They are widely used in wireless (radio) transmission for both transmission and reception.

Telecommunication

telecommunicationscommunicationstelecom
Radio systems used for communication have the following elements.
Telecommunication is the transmission of signs, signals, messages, words, writings, images and sounds or information of any nature by wire, radio, optical or electromagnetic systems.

Phase modulation

phase modulatedPMphase-modulated
Radio systems need a transmitter to modulate (change) some property of the energy produced to impress a signal on it, for example using amplitude modulation or angle modulation (which can be frequency modulation or phase modulation).
Phase modulation is widely used for transmitting radio waves and is an integral part of many digital transmission coding schemes that underlie a wide range of technologies like Wi-Fi, GSM and satellite television.

Radio spectrum

bandradio bandspectrum
"AM" is often used to refer to the medium wave broadcast band (see AM radio), but it is used in various radiotelephone services such as the Citizens Band, amateur radio and especially in aviation, due to its ability to be received under very weak signal conditions and its immunity to capture effect, allowing more than one signal to be heard simultaneously.
To prevent interference between different users, the generation and transmission of radio waves is strictly regulated by national laws, coordinated by an international body, the International Telecommunication Union (ITU).

Radiotelephone

radio telephoneradiotelephonyradiophone
"AM" is often used to refer to the medium wave broadcast band (see AM radio), but it is used in various radiotelephone services such as the Citizens Band, amateur radio and especially in aviation, due to its ability to be received under very weak signal conditions and its immunity to capture effect, allowing more than one signal to be heard simultaneously.
A radiotelephone (or radiophone) is a communications system for transmission of speech over radio.

Radio receiver

receiverreceiversRadios
A radio receiver receives its input from an antenna and converts it into a form that is usable for the consumer, such as sound, pictures, digital data, measurement values, navigational positions, etc. Radio frequencies occupy the range from a 30 Hz to 300 GHz, although commercially important uses of radio use only a small part of this spectrum.
In radio communications, a radio receiver, also known as a receiver, wireless or simply radio is an electronic device that receives radio waves and converts the information carried by them to a usable form.

FM broadcasting

FMFM radioFM band
FM is commonly used at Very high frequency (VHF) radio frequencies for high-fidelity broadcasts of music and speech (see FM broadcasting).
Invented in 1933 by American engineer Edwin Armstrong, wide-band FM is used worldwide to provide high-fidelity sound over broadcast radio.

Polarization (waves)

polarizationpolarizedpolarized light
The transmitter sends the modulated electrical energy to a tuned resonant antenna; this structure converts the rapidly changing alternating current into an electromagnetic wave that can move through free space (sometimes with a particular polarization).
Polarization is an important parameter in areas of science dealing with transverse waves, such as optics, seismology, radio, and microwaves.

Lee de Forest

DeForestLee DeForestDe Forest
Lee de Forest helped popularize the new word in the United States—in early 1907 he founded the DeForest Radio Telephone Company, and his letter in the June 22, 1907 Electrical World about the need for legal restrictions warned that "Radio chaos will certainly be the result until such stringent regulation is enforced".
(De Forest preferred the term "radio", which up to now had been primarily used in Europe, over "wireless".)

Detector (radio)

detectordetectorsratio detector
At the receiver, these currents are demodulated, which is conversion to a usable signal form by a detector sub-system.
In radio, a detector is a device or circuit that extracts information from a modulated radio frequency current or voltage.

Radio broadcasting

radio stationsradio stationradio
FM is commonly used at Very high frequency (VHF) radio frequencies for high-fidelity broadcasts of music and speech (see FM broadcasting).
The earliest radio stations were radiotelegraphy systems and did not carry audio.

Terminal equipment

terminus
A radio communication system requires a transmitter and a receiver, each having an antenna and appropriate terminal equipment such as a microphone at the transmitter and a loudspeaker at the receiver in the case of a voice-communication system.
In radio-relay systems, equipment used at points where data are inserted or derived, as distinct from equipment used only to relay a reconstituted signal.

Transistor

transistorstransistorizeddiscrete transistor
Radio became more useful after the invention of electronic devices such as the vacuum tube and later the transistor, which made it possible to amplify weak signals.
The transistor revolutionized the field of electronics, and paved the way for smaller and cheaper radios, calculators, and computers, among other things.

Resonance

resonantresonant frequencyresonance frequency
The transmitter sends the modulated electrical energy to a tuned resonant antenna; this structure converts the rapidly changing alternating current into an electromagnetic wave that can move through free space (sometimes with a particular polarization).
Electrical resonance of tuned circuits in radios and TVs that allow radio frequencies to be selectively received

Reflection (physics)

reflectionreflectedreflective
Once generated, electromagnetic waves travel through space either directly, or have their path altered by reflection, refraction or diffraction.
Reflection of VHF and higher frequencies is important for radio transmission and for radar.

Technology

technologiestechnologicaltechnical
Radio is the technology of using radio waves to carry information, such as sound and images, by systematically modulating properties of electromagnetic energy waves transmitted through space, such as their amplitude, frequency, phase, or pulse width.
Communication was also greatly improved with the invention of the telegraph, telephone, radio and television.

Photophone

transmit sound
It was first applied to communications in 1881 when, at the suggestion of French scientist Ernest Mercadier, Alexander Graham Bell adopted "radiophone" (meaning "radiated sound") as an alternate name for his photophone optical transmission system.
The telephone itself was still something of a novelty, and radio was decades away from commercialization.

Microwave

microwavesmicrowave radiationmicrowave tube
An August 1894 lecture by the British physicist Oliver Lodge, where he transmitted and received "Hertzian waves" at distances up to 50 meters, was followed up the same year with experiments by Bengali physicist Jagadish Chandra Bose in extremely high frequency radio microwave optics and a year later with the construction of a radio based lightning detector by Russian physicist Alexander Stepanovich Popov.
The boundaries between far infrared, terahertz radiation, microwaves, and ultra-high-frequency radio waves are fairly arbitrary and are used variously between different fields of study.

Electromagnetic interference

interferenceradio frequency interferenceradio interference
Noise will generally alter the desired signal; this electromagnetic interference comes from natural sources, as well as from artificial sources such as other transmitters and accidental radiators.
Interference with the meaning of electromagnetic interference, also radio-frequency interference (short: EMI | RFI) is – according to Article 1.166 of the International Telecommunication Unions (ITU) Radio Regulations (RR) – defined as «''The effect of unwanted energy due to one or a combination of emissions, radiations, or inductions upon reception in a radiocommunication system, manifested by any performance degradation, misinterpretation, or loss of information which could be extracted in the absence of such unwanted energy''».