Library Concept
Quadrature
Two periodic signals offset by exactly a quarter cycle (90°) — the relationship behind quadrature oscillators, phase detection, and stereo/spatial encoding.
A special case of phase offset in which two periodic signals of the same frequency differ by exactly a quarter cycle, 90°. A pair of quadrature signals — commonly labeled I (in-phase) and Q (quadrature) — carries more information than either alone, since their relative sign and magnitude encode direction as well as magnitude; the relationship is used to detect phase and frequency error in a phase-locked loop, to build oscillators that output sine and cosine simultaneously, and in stereo and spatial audio encoding.