Phase Modulation

Phase Modulation

Phase modulation (PM) is a form of modulation that represents information as variations in the instantaneous phase of a carrier wave.We can say that modification in phase according to low frequency will give phase modulation.

Unlike its more popular counterpart, frequency modulation (FM), PM is not very widely used for radio transmissions. This is because it tends to require more complex receiving hardware and there can be ambiguity problems in determining whether, for example, the signal has changed phase by +180° or -180°. PM is used, however, in digital music synthesizers such as the Casio CZ synthesizers, or to implement FM Synthesis in digital synthesizers such as the Yamaha DX7. (see FM Synthesis)

Read more about Phase Modulation:  Theory, Modulation Index

Other articles related to "phase, phase modulation, modulation":

Supercontinuum - Historical Overview - The 1980s
... The phase-matching condition was met by coupling of the up-converted light and the quasi-continuum of cladding modes ... It was realised that self-phase modulation could not account for the broad continua seen, but for the most part little else was offered as an explanation ... that the spectral broadening due to self-phase modulation should have been 910 cm−1, but their continuum was greater than 3000 cm−1 ...
Télé Distribution Française - Phase Modulation Pattern
... One signal element consists of the phase of the carrier shifted linearly by +1 rad in 25 ms (known as "ramp A"), then shifted linearly by −2 rad over 50 ... ramp B of the initial signal element, the exact point the signal phase is at zero represents the top of the UTC second ... Since the phase is the integral of the frequency, this triangular phase modulation corresponds to a square frequency modulation with an amplitude of about ±6 Hz ...
Radio Transmitter Design - Frequency Mixing and Modulation - FM Modes - Indirect FM
... FM employs a varicap diode to impose a phase shift (which is voltage-controlled) in a tuned circuit that is fed with a plain carrier ... This is termed phase modulation ... The modulated signal from a phase-modulated stage can be understood with an FM receiver, but for good audio quality, the audio is applied to the phase modulation stage ...
Phase Modulation - Modulation Index
... As with other modulation indices, this quantity indicates by how much the modulated variable varies around its unmodulated level ... It relates to the variations in the phase of the carrier signal , where is the peak phase deviation ... Compare to the modulation index for frequency modulation ...
Self-phase Modulation
... Self-phase modulation (SPM) is a nonlinear optical effect of light-matter interaction ... This variation in refractive index will produce a phase shift in the pulse, leading to a change of the pulse's frequency spectrum ... Self-phase modulation is an important effect in optical systems that use short, intense pulses of light, such as lasers and optical fibre communications systems ...

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