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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 modulation, it uses transmitter power and bandwidth more efficiently.
Most amateur digital modes are transmitted by inserting audio into the microphone input of a radio and using an analog scheme, such as amplitude modulation (AM), frequency modulation (FM), or single-sideband modulation (SSB). Amateur teleprinting over radio (AMTOR) D-STAR (Digital Data) a high speed (128 kbit/s), data-only mode.
The power of an AM radio signal plotted against frequency. fc is the carrier frequency, fm is the maximum modulation frequency. In radio communications, a sideband is a band of frequencies higher than or lower than the carrier frequency, that are the result of the modulation process. The sidebands carry the information transmitted by the radio ...
Double-sideband amplitude modulation (e.g. AM broadcast radio) B: Independent sideband (two sidebands containing different signals) C: Vestigial sideband (e.g. NTSC) D: Combination of AM and FM or PM F: Frequency modulation (e.g. FM broadcast radio) G: Phase modulation: H: Single-sideband modulation with full carrier (e.g. as used by CHU) J
Independent sideband (ISB) is an AM single sideband mode which is used with some AM radio transmissions. Normally each sideband carries identical information, but ISB modulates two different input signals — one on the upper sideband, the other on the lower sideband. This is used in some kinds of AM stereo (sometimes known as the Kahn system).
CESSB (controlled-envelope single-sideband) is a narrowband modulation method using a single sideband, whose peak envelope level is controlled so that the peak-to-average power ratio of CESSB is much reduced compared to standard SSB modulation and offers improved effective range over standard SSB modulation while simultaneously retaining backwards compatibility with standard SSB radios.
SSB, or SSB-AM single-sideband full carrier modulation, is very similar to single-sideband suppressed carrier modulation (SSB-SC). It is used where it is necessary to receive the audio on an AM receiver, while using less bandwidth than with double sideband AM. Due to high distortion, it is seldom used.
A Compatible sideband transmission, also known as amplitude modulation equivalent (AME) or Single sideband reduced-carrier (SSB-RC), is a type of single sideband RF modulation in which the carrier is deliberately reinserted at a lower level after its normal suppression to permit reception by conventional AM receivers. The general convention is ...