Single Sideband Modulation (SSB)

Single Sideband Modulation is an optimization of Amplitude Modulation. Only one of the two sidebands - the upper or the lower one - is transmitted. Since all the relevant information is contained in one of the sidebands, the carrier frequency must not be transmitted. An SSB radio, that only transmits the frequency spectrum between 300 Hz and 2700 Hz necessary for voice recognition, just needs a bandwidth of 2.4 kHz.