What are Radio Waves?
Radio waves are an electromagnetic wave with the longest wavelength (low frequency). Radio waves are natural emitted by stars but they can be artificial created by making the particles in metal to vibrate. Radio waves are received by televisions, phones and radios to be converted into vibrations which can be used to create sound. This allows us to get updated on news, music, and latest trends (on the radio). Radio waves are capable of sending information in the form of waves, wirelessly.
Digital vs Analogue
Radios can be digital and analogue.
DIGITAL
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ANALOGUE
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How do digital radios work?
Digital radios work by turning the sounds into a digital signal (which is a pattern of binary digits; 0 and 1) unlike analogues which converts it into an electrical signal. The digital signal is then transmitted and when received by a digital radio receiver it is decoded to the original sounds. Each digit is used for each note of the sound and so when songs are played, they are actually separate individual notes rather than a continuous melody (unlike analogue). Digital signals are different from the signals that are sent by AM and FM radios.
How do analogue radios work?
We are able to hear music or conversations on the radio because it receives a signal.
All the things we hear on the radio comes from the radio broadcasting station which is a one-way wireless transmission of information through radio waves. In order to send out the waves, we need a transmitter which is a metal rod with the particles inside made to vibrate (creating radio waves). Back at the radio station, they are transmitting sound signals (e.g. music) that will be converted into an electrical signal. This electrical signal is called an audio wave. The audio wave will |
be added to the carrier wave (radio wave that carries the signal). This will either create a FM or AM radio wave (modulated waves). These waves send a continuous signal. Radio waves travel through the air at 300 000 km/sec. These waves will be received by a receiver (in your car) which is just like a transmitter. Your radio will then take away the carrier wave from the modulated wave, leaving behind the audio signal which will be amplified and be sent to the speaker to be heard as sounds.
When you are tuning into the radio, you are actually selecting the frequency of the carrier wave you want to receive.
When you are tuning into the radio, you are actually selecting the frequency of the carrier wave you want to receive.
AM and FM
When the signal is sent out from the transmitter they travel in one of the two ways.
AM stands for amplitude modulation. This is when the audio signal changes the amplitude of the carrier wave because it is where the information is 'stored'. AM carrier waves have frequencies ranging from about 540 kilohertz to about 1600 kilohertz.
FM on the other hand stands for frequency modulation. It is when the frequency of the carrier wave is changed - making some parts of the wave more compressed than others. FM carrier waves have are much higher - from about 88 megahertz and 108 megahertz. (I megahertz equals 1 million hertz)
AM stands for amplitude modulation. This is when the audio signal changes the amplitude of the carrier wave because it is where the information is 'stored'. AM carrier waves have frequencies ranging from about 540 kilohertz to about 1600 kilohertz.
FM on the other hand stands for frequency modulation. It is when the frequency of the carrier wave is changed - making some parts of the wave more compressed than others. FM carrier waves have are much higher - from about 88 megahertz and 108 megahertz. (I megahertz equals 1 million hertz)
FM vs AM
FM
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AM
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