- Quadrature
Quadrature, derived from Latin "quadrare", may refer to:
In signal processing:
*Quadrature amplitude modulation (QAM), a modulation method of using both a carrier wave and a 'quadrature' carrier wave that is 90° out of phase with the main carrier
*Quadrature phase , oscillations that are said to be "in quadrature" if they are separated in phase by 90° (π/2, or λ/4)
*Quadrature filter , the analytic signal of a real-valued filter
*Quadrature coupler, see under chapter five inPower dividers and directional couplers In mathematics:
*Quadrature of the circle (also "squaring the circle"), in geometry, the problem of constructing a square and circle of equal area, impossible using only an unmarked straight-edge and compass
*"Summing in quadrature" means summing the squares of numbers, then taking the square root, as used in error analysis
*Numerical integration , the numerical calculation of the area under a curve, or more generally, using numerical integration to calculate a definite integralQuadrature may also refer to:
*In motion control, "quadrature encoder" is arotary encoder orlinear encoder giving both the relative position and the direction of motion of a shaft
*Inastronomy , quadrature occurs when two celestial bodies appear 90° apart from one another as viewed from a third celestial body. As an example, the Moon and the Sun are in quadrature with respect to the Earth when the Moon is in its exact first quarter or last quarter phases. The symbol for astronomical quadrature is a hollow square
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