phquad

Phquad is a term that appears primarily as an informal shorthand in certain communities to refer to a phase-quadrature pair in signal processing. It is not a standard term in textbooks or industry standards, and there is no single, universally accepted definition. In this sense, phquad denotes two signals or components that are 90 degrees out of phase and often have related amplitudes, commonly described as the in-phase (I) and quadrature (Q) components of a complex baseband signal. The phquad representation underpins the analytic signal concept and is central to many digital modulation and demodulation techniques, such as quadrature amplitude modulation (QAM) and IQ demodulation, where a real-valued waveform is decomposed into I and Q channels for processing.

Phquad is sometimes used in code, discussions, or notes as a mnemonic for the pair (I, Q) or as a variable name. In practice, however, the same concept is more often described using the terms “I/Q pair,” “quadrature components,” or “analytic signal.” Because phquad lacks formal status, its meaning can vary by context, and readers should rely on explicit definitions in any given document.

Related topics include phase, quadrature, analytic signal, Hilbert transform, and QAM. If encountered in literature or software, phquad should be defined locally to avoid ambiguity.