A Compatible sideband transmission, also known as

amplitude modulation Amplitude modulation (AM) is a modulation technique used in electronic communication, most commonly for transmitting messages with a radio wave. In amplitude modulation, the amplitude (signal strength) of the wave is varied in proportion to ...

equivalent (AME) or

Single sideband In radio communications, single-sideband modulation (SSB) or single-sideband suppressed-carrier modulation (SSB-SC) is a type of modulation used to transmit information, such as an audio signal, by radio waves. A refinement of amplitude modul ...

reduced-carrier (SSB-RC), is a type of

single sideband In radio communications, single-sideband modulation (SSB) or single-sideband suppressed-carrier modulation (SSB-SC) is a type of modulation used to transmit information, such as an audio signal, by radio waves. A refinement of amplitude modul ...

modulation In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the ''carrier signal'', with a separate signal called the ''modulation signal'' that typically contains informatio ...

in which the

carrier Carrier may refer to: Entertainment * ''Carrier'' (album), a 2013 album by The Dodos * ''Carrier'' (board game), a South Pacific World War II board game * ''Carrier'' (TV series), a ten-part documentary miniseries that aired on PBS in April 20 ...

is deliberately reinserted at a lower level after its normal suppression to permit reception by conventional AM receivers. The general convention is to filter the lower-sideband, and communicate using only the upper-sideband and a partial carrier. The benefits of compatible-sideband over conventional AM are increased

spectral efficiency Spectral efficiency, spectrum efficiency or bandwidth efficiency refers to the information rate that can be transmitted over a given bandwidth in a specific communication system. It is a measure of how efficiently a limited frequency spectrum is ut ...

due to a reduction in bandwidth of 50% as well as a decrease in wasted power. By using compatible sideband instead of AM, less RF power is required at the transmitter to transmit the same quality of signal the same distance. This results in compatible sideband being almost 100% power-efficient, where regular AM is comparably only 16% power-efficient (84% of RF power wasted). This modulation is currently mostly used in

high frequency High frequency (HF) is the ITU designation for the range of radio frequency electromagnetic waves (radio waves) between 3 and 30 megahertz (MHz). It is also known as the decameter band or decameter wave as its wavelengths range from one to ten ...

military communications.

References

Radio modulation modes {{telecomm-stub