SSB

Single-sideband modulation (SSB) is a refinement of amplitude modulation that more efficiently uses electrical power and bandwidth
The method by which audio, (information), is impressed on a radio signal is called modulation. To modulate a radio wave is to add information to it that can be received on a receiver for some useful purpose. It is a very efficient method of superimposing your voice or other information on a radio wave and the transmission of that radio wave.

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