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A modulator is a device or circuit that performs modulation. A demodulator (sometimes detector ) is a circuit that performs demodulation , the inverse of modulation. A modem (from mod ulator– dem odulator), used in bidirectional communication, can perform both operations.
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).
Demodulation is the process of extracting the original information-bearing signal from a carrier wave. A demodulator is an electronic circuit (or computer program in a software-defined radio) that is used to recover the information content from the modulated carrier wave. [1] There are many types of modulation, and
Delta-sigma modulation is related to delta modulation by the following steps (Figure 7): [11] §6. Start with a block diagram of a delta modulator/demodulator. The linearity property of integration, + = (+), makes it possible to move the integrator from the demodulator to be before the summation.
E represents the envelope term; roughly half the modulation term applied to the envelope modulator is utilized to reduce the second-order term of the arcsin "phase"-modulated path; thus reducing the second-order term in the undesired sideband. A multi-loop modulator/demodulator feedback approach was used to generate an accurate arcsin signal.
A phase-locked loop or phase lock loop (PLL) is a control system that generates an output signal whose phase is fixed relative to the phase of an input signal. Keeping the input and output phase in lockstep also implies keeping the input and output frequencies the same, thus a phase-locked loop can also track an input frequency.
Therefore, the further the points are separated from one another, the greater the noise immunity of the modulation. Practical modulation systems are designed to maximize the minimum noise needed to cause a symbol error; on the constellation diagram this means that the distance between each pair of adjacent points is equal.
A modulator-demodulator, commonly referred to as a modem, is a computer hardware device that converts data from a digital format into a format suitable for an analog ...