Quadrature may refer to:

Mathematics

Quadrature (geometry) In mathematics, quadrature is a historic term for the computation of area (mathematics), areas and is thus used for computation of integrals. The word is derived from the Latin ''quadratus'' meaning "square". The reason is that, for Ancient Gr ...

, drawing a square with the same area as a given plane figure (''squaring'') or computing that area **

Quadrature of the circle Squaring the circle is a problem in geometry first proposed in Greek mathematics. It is the challenge of constructing a square (geometry), square with the area of a circle, area of a given circle by using only a finite number of steps with a ...

** ''

Quadrature of the Parabola ''Quadrature of the Parabola'' () is a treatise on geometry, written by Archimedes in the 3rd century BC and addressed to his Alexandrian acquaintance Dositheus. It contains 24 propositions regarding parabolas, culminating in two proofs showing t ...

'' ** Quadrature of the hyperbola *

Numerical integration In analysis, numerical integration comprises a broad family of algorithms for calculating the numerical value of a definite integral. The term numerical quadrature (often abbreviated to quadrature) is more or less a synonym for "numerical integr ...

is often called "numerical quadrature" or simply "quadrature" **

Gaussian quadrature In numerical analysis, an -point Gaussian quadrature rule, named after Carl Friedrich Gauss, is a quadrature rule constructed to yield an exact result for polynomials of degree or less by a suitable choice of the nodes and weights for . Th ...

, a special case of numerical integration * Quadrature (differential equations), expressing a differential equation solution in terms of integrals. * Formerly, a synonym for "integral" **

Integral In mathematics, an integral is the continuous analog of a Summation, sum, which is used to calculate area, areas, volume, volumes, and their generalizations. Integration, the process of computing an integral, is one of the two fundamental oper ...

Antiderivative In calculus, an antiderivative, inverse derivative, primitive function, primitive integral or indefinite integral of a continuous function is a differentiable function whose derivative is equal to the original function . This can be stated ...

Signal processing

* Addition in quadrature, combining the magnitude of uncorrelated signals by taking the square root of the sum of their squares *

Quadrature phase In physics and mathematics, the phase (symbol φ or ϕ) of a wave or other periodic function F of some real variable t (such as time) is an angle-like quantity representing the fraction of the cycle covered up to t. It is expressed in such a s ...

, oscillations that are said to be ''in quadrature'' if they are separated in phase by 90° (/2, or /4) *

Quadrature component A sinusoid with modulation can be decomposed into, or synthesized from, two amplitude-modulated sinusoids that are in quadrature phase, i.e., with a phase offset of one-quarter cycle (90 degrees or /2 radians). All three sinusoids have the sam ...

of a composite signal * Quadrature filter, the analytic signal of a real-valued filter *

Quadrature amplitude modulation Quadrature amplitude modulation (QAM) is the name of a family of digital modulation methods and a related family of analog modulation methods widely used in modern telecommunications to transmit information. It conveys two analog message signa ...

(QAM), a modulation method of using both an (in-phase) carrier wave and a 'quadrature' carrier wave that is 90° out of phase with the main, or in-phase, carrier *

Quadrature phase-shift keying Phase-shift keying (PSK) is a digital modulation process which conveys data by changing (modulating) the phase of a constant frequency carrier wave. The modulation is accomplished by varying the sine and cosine inputs at a precise time. It is ...

(QPSK), a phase-shift keying of using four quadrate points on the constellation diagram, equispaced around a circle

Science

* Optical phase space quadratures, operators which represent the real and imaginary parts of the complex amplitude *

Quadrature (astronomy) In spherical astronomy, quadrature is the configuration of a celestial object in which its elongation is a right angle (90 degrees), i.e., the direction of the object as viewed from Earth is perpendicular to the position of the Sun relative to ...

, the position of a body (moon or planet) such that its elongation is 90° or 270°; i.e., the body-earth-sun angle is 90°

Other uses

Quadrature encoder An incremental encoder is a linear or rotary electromechanical device that has two output signals, ''A'' and ''B'', which issue pulses when the device is moved. Together, the ''A'' and ''B'' signals indicate both the occurrence of and direction ...

, a device that detects mechanical position changes and direction of movement *

Illusionistic ceiling painting Illusionistic ceiling painting, which includes the techniques of perspective di sotto in sù and quadratura, is the tradition in Renaissance, Baroque and Rococo art in which '' trompe-l'œil'', perspective tools such as foreshortening, and othe ...

, sometimes called ''quadrature'' after the Italian term, ''quadratura'' *

La Quadrature du Net La Quadrature du Net ('' Squaring the Net'' in French) is a French advocacy group that promotes digital rights and freedoms for its citizens. It advocates for French and European legislation to respect the founding principles of the Internet, m ...

(Squaring of the Net in French), a French advocacy group that promotes digital rights and freedoms of citizens * "Quadrature", a song by Squarepusher from the album ''

Just a Souvenir ''Just a Souvenir'' is the ninth album by Squarepusher, released in October 2008. The album originated in a daydream, in which Tom Jenkinson envisioned a rock band performing a concert against the backdrop of a large, glowing coathanger. The ...

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