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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.
For example, Morse code sent by in an AM broadcast by a commercial radio station would be modulated CW as it contains a subcarrier. This mode is designated A2A by the Federal Communications Commission. The symbols stand for: A (amplitude modulation), 2 (one channel containing digital information, using a subcarrier), A (aural telegraphy).
Although average power is the same as PEP for complex modulation forms, such as FSK, the peak envelope power bears no particular ratio or mathematical relationship to longer-term average power in distorted envelopes, such as a CW waveform with power overshoot, or with amplitude modulated waveforms, such as SSB or AM voice transmissions. Typical ...
Signalling by keying the carrier directly, a.k.a. continuous wave (CW) or on–off keying, currently used in amateur radio. This is often but not necessarily Morse code. A2A Signalling by transmitting a modulated tone with a carrier, so that it can easily be heard using an ordinary AM receiver.
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.
A continuous wave or continuous waveform (CW) is an electromagnetic wave of constant amplitude and frequency, typically a sine wave, that for mathematical analysis is considered to be of infinite duration. [1] It may refer to e.g. a laser or particle accelerator having a continuous output, as opposed to a pulsed output.
Before vacuum tube oscillators were invented, the first CW receivers used a wheel with electrical contacts around its rim, spun at a high speed by a motor, to interrupt a current to create a radio frequency signal to beat with the incoming radio signal. This example, at the Tuckerton transatlantic receiving station in New Jersey in 1917 ...
Most amateur organizations agree that for CW, AM, FM, and data modes, the transmitter output power should be 5 watts (or less). [9] The maximum output power for SSB (single sideband) is sometimes agreed to be no more than 10 Watts peak envelope power (PEP), while some organisations opine that the power limit should be 5 Watts. QRPers are known ...