Single Side Band - Amplitude Modulated signals transmitted using only one side band, often with suppressed carrier.

While summing two signals for amplitude modulation, two image signals are formed. To keep the bandwidth requirements low, one side band is discarded and only side band is transmitted. The side band above the carrier frequency is called the Upper Side Band and the frequency lower than the carrier is called the Lower Side Band. To conserve transmitter power, often the carrier is discarded as well.