Radio signals are used to carry information. Some are used for carrying sound broadcasting, others are used for mobile telephone communications. In fact there is an almost infinite variety of uses for radio signals, but in all cases they are used to carry information in one form or another.

To be able to transmit any form of information a radio signal or carrier is first generated. The information in the form of audio, data, or other form of signal is used to modify or modulate the carrier and in this way the information is superimposed onto the carrier and is transmitted to the receiver. Here the information is removed from the radio signal and reconstituted in its original format by a process known as demodulation.

There are many ways ...

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