# phase modulation

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Related to phase modulation: frequency modulation, amplitude modulation

## phase modulation:

see modulationmodulation,
in communications, process in which some characteristic of a wave (the carrier wave) is made to vary in accordance with an information-bearing signal wave (the modulating wave); demodulation is the process by which the original signal is recovered from the wave
.

## Phase Modulation

a method of modulating oscillations in which the transmitted signal controls the phase of a high-frequency carrier. The characteristics of phase modulation are similar to those of frequency modulation. If the modulating signal is sinusoidal, the spectra and wave forms of phase-modulated and frequency-modulated signals coincide. Differences between the two methods become apparent if the modulating signal has a more complex wave form.

## phase modulation

[′fāz ‚mäj·ə‚lā·shən]
(communications)
Modulation in which the linearly increasing angle of a sine wave has added to it a phase angle that is proportional to the instantaneous value of the modulating signal (message to be communicated). Abbreviated PM.

## phase modulation

A method of modulating a sine-wave carrier, so its phase is changed by an amount proportional to the instantaneous value of the modulating voltage.

## phase modulation

Varying the angle of a wave in a carrier in order to transmit analog or digital data. For digital signals, phase modulation (PM) is widely used in conjunction with amplitude modulation (AM). For example, quadrature amplitude modulation (QAM) uses both phase and amplitude modulation to create different binary states for transmission (see QAM). See modulation and carrier.

Vary the Angle In PM modulation, the angle of the carrier wave is varied by the incoming signal. In this example, the modulating wave implies an analog signal.

Digital Phase Shift Keying (PSK) For digital signals, phase shift keying (PSK) uses two phases for 0 and 1 as in this example. See DPSK.
References in periodicals archive ?
The second simulation model was an 8 channel DWDM transmission system with an in-line FOPA, used to estimate how pump phase modulation influences the spectrum of the produced idlers.
1] has large influence on the phase modulation of the diffracted TM mode, the phase detection is a strong way to find the index.
There are also more complex phase modulations in which there are many defined phases, so there can be more bits carried per baud.
Phase modulation of the pump was required in order to broaden the spectrum of the pumping radiation, in such a way mitigating the impact of stimulated Brillouin scattering.
Peak phase modulation [delta][theta] and peak frequency modulation [delta]f are related as follows:
The power-distribution characteristic varies with the type of phase modulation used, but the effective bandwidth is of the order of magnitude of one divided by the chip rate.
The devices current mode architecture, clock output and phase modulation enable easy paralleling of multiple devices for up to 12-phase operation for very high power applications.
In this research we used three methods (continuous wave self phase modulation (CW SPM), pulse phase self-modulation (P-SPM) and cross phase modulation (XPM)), but better results, compared simulations and experiments, we obtained by the P-SPM method.
The multi-level modulation using phase modulation or digital coherent detection is being introduced into 40Gbps and 100Gbps optical transmissions compared with traditional On-Off Keying (OOK), since these are not easily affected by signal distortion and noise caused by transmission fibers.
Phase jitter will show itself as residual phase modulation.

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