is the frequency range over which an equipment operates or the portion of the spectrum occupied by the signal
Bandwidth?is also defined as the amount of data that can be transmitted in a fixed amount of time. For digital devices, the?bandwidth?is usually expressed in bits per second(bps) or bytes per second. For analog devices, the?bandwidth?is expressed in cycles per second, or Hertz (Hz).
superimposing low frequency message on a high frequency wave carrier
In electronics and telecommunications,?modulation?is the process of varying one or more properties of a periodic waveform, called the carrier signal, with a?modulatingsignal that typically contains information to be transmitted.
AM/FM
Modulation used in radio is generally AM/FM
Recovering the low frequency modulating signal from the received signal
Demodulation?is extracting the original information-bearing signal from a modulated carrier wave. A?demodulator?is an electronic circuit (or computer program in a software-defined radio) that is used to recover the information content from the modulated carrier wave.
extending communication range
In telecommunications, a?repeater?is an electronic device that receives a signal and retransmits it at a higher level or higher power, or onto the other side of an obstruction, so that the signal can cover longer distances.