Fasedef

Fasedef is a term encountered in a variety of technical contexts to denote the formal definition of the phase component associated with a signal, field, or dataset. It is not a standard term with a single consensus meaning; its exact scope depends on the domain and the software or data model in use. In general, a fasedef specifies how phase is measured, represented, and interpreted, including conventions for reference frequency or time, angular units (degrees or radians), and the sign of phase progression.

A typical fasedef describes either a phase function φ that maps time, frequency, or both to a phase angle, or a set of phase values linked to spectral components or channels. It may also include metadata such as the reference channel, the base frequency, phase wrap handling, and any phase calibration factors. Because phase is inherently comparative, fasedefs often accompany amplitude or magnitude definitions and are used to preserve phase relationships during processing, alignment, or reconstruction.

Applications of fasedef concepts appear in signal processing, telecommunications, optics, radio astronomy, and audio synthesis. In these fields, a fasedef facilitates consistent interpretation of phase information across systems, enables phase calibration, and supports algorithms that depend on phase such as demodulation, beamforming, or holography. Fasedef representations are commonly serialized in JSON, XML, or YAML in research pipelines, though some domains rely on custom binary formats for performance.

Because fasedef is not standardized, implementations vary widely. Users should document the chosen conventions within their data models and ensure that consumers of the data agree on reference frames, units, and wrap behavior to avoid misinterpretation.