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Categorization for signal modulation based on data and carrier types. 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 information to be transmitted. [1]
Frequency modulation (FM) is the encoding of information in a carrier wave by varying the instantaneous frequency of the wave. The technology is used in ...
In telecommunications, a carrier wave, carrier signal, or just carrier, is a periodic waveform (usually sinusoidal) that conveys information through a process called modulation. One or more of the wave's properties, such as amplitude or frequency, are modified by an information bearing signal, called the message signal or modulation signal.
In laser physics and engineering, "continuous wave" or "CW" refers to a laser that produces a continuous output beam, sometimes referred to as "free-running," as opposed to a q-switched, gain-switched or modelocked laser, which has a pulsed output beam. The continuous wave semiconductor laser was invented by Japanese physicist Izuo Hayashi in 1970.
The phase modulation (φ(t), not shown) is a non-linearly increasing function from 0 to π /2 over the interval 0 < t < 16. The two amplitude-modulated components are known as the in-phase component (I, thin blue, decreasing) and the quadrature component (Q, thin red, increasing).
Chirp modulation, or linear frequency modulation for digital communication, was patented by Sidney Darlington in 1954 with significant later work performed by Winkler [who?] in 1962. This type of modulation employs sinusoidal waveforms whose instantaneous frequency increases or decreases linearly over time.
In physics and engineering, the envelope of an oscillating signal is a smooth curve outlining its extremes. [1] The envelope thus generalizes the concept of a constant amplitude into an instantaneous amplitude. The figure illustrates a modulated sine wave varying between an upper envelope and a lower envelope. The envelope function may be a ...
This negative damping is due to a positive feedback between the oscillation and the modulation of the external source of power. The amplitude and waveform of steady self-oscillations are determined by the nonlinear characteristics of the system. Self-oscillations are important in physics, engineering, biology, and economics.