how do radio stations transmit music on air?

Answer 1

The Radio stations are of several types. The best known are the AM and FM stations; these include both commercial, public and nonprofit varieties as well as student-run campus radio stations found and hospital radio stations can be found throughout the developed world.

AM
AM stations were the earliest broadcasting stations to be developed. AM refers to amplitude modulation, a mode of broadcasting radio waves by varying the amplitude of the carrier signal in response to the amplitude of the signal to be transmitted.

One of the advantages of AM is that its unsophisticated signal can be detected (turned into sound) with simple equipment. If a signal is strong enough, not even a power source is needed; building an unpowered crystal radio receiver was a common childhood project in the early years of radio.

AM broadcasts occur on North American airwaves in the mediumwave frequency range of 530 to 1700 kHz (known as the "standard broadcast band"). The band was expanded in the 1990s by adding nine channels from 1620 to 1700 kHz. Channels are spaced every 10 kHz in the Americas, and generally every 9 kHz everywhere else.

AM radio transmitters transmit audio frequencies up to 15 kHz, but most receivers are only capable of reproducing frequencies up to 5 kHz. At the time that AM broadcasting began in the 1920s, this provided adequate fidelity for existing microphones, 78 rpm recordings, and loudspeakers. The fidelity of sound equipment subsequently improved considerably but the receivers did not. Reducing the bandwidth of the receivers reduces the cost of manufacturing and makes them less prone to interference. In the United States, AM stations are never assigned adjacent channels in the same service area. This prevents the sideband energy generated by two stations from interfering with each other.Bob Carver created an AM tuner employing notch filtering that demonstrated an AM broadcast can exceed the 15 kHz bandwidth of FM stations without objectionable interference. His expensive tuner was never widely adopted, and became obsolete with the advent of HD Radio.

FM
FM refers to frequency modulation, and occurs on VHF airwaves everywhere (except Japan) in the frequency range of 88 to 108 MHz. Japan uses the 76 to 90 MHz band. FM stations are much more popular in economically developed regions, such as Europe and the United States, especially since higher sound fidelity and stereo broadcasting became common in this format.

In fact 200 kHz is not needed to accommodate an audio signal — 20 kHz to 30 kHz is all that is necessary for a narrowband FM signal. The 200 kHz bandwidth allowed room for ±75 kHz signal deviation from the assigned frequency plus a 50 kHz guardband to eliminate adjacent channel interference. The larger bandwidth allows for broadcasting a 15 kHz bandwidth audio signal plus a 38 kHz stereo "subcarrier" — a piggyback signal that rides on the main signal. Additional unused capacity is used by some broadcasters to transmit utility functions such as background music for public areas, GPS auxiliary signals, or financial market data.

Digital
Digital radio broadcasting has emerged, first in Europe (the UK in 1995 and Germany in 1999), and later in the United States. The European system is named DAB, for Digital Audio Broadcasting, and uses the public domain EUREKA 147 system. In the United States, the IBOC system is named HD Radio and owned by a consortium of private companies called iBiquity. An international non-profit consortium Digital Radio Mondiale (DRM), has introduced the public domain DRM system.

It is expected that for the next 10 to 20 years, all these systems will co-exist, while by 2015 to 2020 digital radio may predominate, at least in the developed countries.

Answer 2

i dont know what r u doing now. If u r reading intermediate or at high school i am happy to see such type of question. this is a large question to answer. to know read communication book. i am trying to understandble u as a layman. Generally the sound has some frequency but it is too low we cant transmit over a larege distance. we are mixing this sound with another frequecncy called carrier frequency. This carrier has a higher frequency. The mixing are also different type. the basic two are Amplitude modulation and Frequency modulation. In amplitude modulation we are mixing frequency of carrier and amplitude of our original music. this i8s done at sending point. At receiving point we are seperating this carrier from the original and u r ablle to listen the music.

Answer 3

hi
not only the music but also all the electrical signals u can transmitt thorugh air.
one question.do u see the sound waves?
but u can feel by listening to them.
As sound waves have lesser frequency about 20 -20KHz, they cannot be transmitted for much distane.Incase to transmitt them for a long distance ,a procedure called MODULATION is used.this is the process of mixing the lower frequency signal with the higher frequency signal.by that the lower frequency signal can be transmitted for long distances.
As ur question relates to this only that the radio stations r units which r programmed to mix different signals of different data.

Answer 4

There is a process called MODULATION in which the characteristics of one wave ( voice signal or signal of tat kind) is (can be colloquially told as) adjusted to another wave for the purpose of transmission as sound waves cannot travel long & high...It means the data about one wave is carried by another wave called the carrier wave.. and the carrier wave is transmitted on air.. ur radio receives the wave & separates the carrier wave & the original wave.. If the amplitude of the original wave is modulated to be transmitted by the carrier wave, then it is amplitude modulation(AM) &if it is frequency,then it is frequency modulation (FM)

Answer 5

They start with a basic single frequency (tone) radio signal and change one of its characteristics based on the content of the music. The most common changes to the radio signal (called the carrier) are changes in its strength (amplitude modulation a.k.a - AM radio) or its frequency (FM modulation). Try this site for more detail ---

http://en.wikipedia.org/wiki/Modulation

Answer 6

Smooth is a great station and plays fab tunes, I listen all the time its on 100.4 fm although its not just soul they do have a couple of shows ie Richard Searling one time DJ at Wigan Casino is on sat nights. Andy Peebles another soulie. Give it a try.

Answer 7

Just like your cell phone.

It is call broadcasting equipment.