# Definition of *quadrature* in English:

## quadrature^{}

### Pronunciation /ˈkwädrəCHər/ /ˈkwɑdrətʃər/

### noun

1Mathematics

The process of constructing a square with an area equal to that of a circle, or of another figure bounded by a curve.

*‘Craig published several more papers on the logarithmic curve, the curve of quickest descent and quadrature of figures.’*

*‘He generalised Gauss's method of quadrature and expressed the polynomials which are involved as a determinant.’**‘This book is a treatise on infinite series, summation, interpolation and quadrature.’**‘He also considered curves of double curvature on the sphere and the quadrature of parts of a spherical surface.’**‘Both in-phase and quadrature measurements are recorded.’*

2Astronomy

The position of the moon or a planet when it is 90° from the sun as viewed from the earth.

*‘When the Sun-Moon system is in quadrature relative to the Earth, the combined gravitational forces are not as strong.’*

*‘The planet is at east quadrature (ninety degrees east of the Sun) on the 26th.’*

3Electronics

A phase difference of 90° between two waves of the same frequency, as in the color difference signals of a television screen.

*‘The MT312 is a single-chip variable rate digital quadrature phase shift keying satellite demodulator.’*

*‘The L5 signal that will appear with the Block IIF satellites in 2006, will have quadrature phase skip keying.’**‘The quadrupolar echo pulse sequence was employed using quadrature detection with complete phase cycling of the pulse pairs.’**‘It features RS - 422-compatible quadrature output, and programmable resolution and output frequency.’**‘A method and apparatus for equalizing a received quadrature amplitude modulated signal is disclosed.’*

**Origin**

Mid 16th century (as a mathematical term): from Latin quadratura ‘a square, squaring’, from quadrare (see quadrate).