For example, a quadrature of the circle, Lune of Hippocrates, The Quadrature of the Parabola. QAM is a digital television standard using quadrature amplitude modulation. For its modulation TETRA, uses differential quadrature phase-shift keying. The fastest four modes use OFDM with forms of quadrature amplitude modulation. The amplitude modulated sinusoids are known as the in-phase and quadrature components. Additional improvements were introduced via the quadrature amplitude modulation (QAM) encoding system. Fiber optic systems can be upgraded by the use of quadrature amplitude modulation. The integral may be efficiently computed by Gaussian quadrature. Deterministic approximations are discussed in quadrature. There are many algorithms for computing the nodes and weights of Gaussian quadrature rules. These zeros play an important role in numerical integration based on Gaussian quadrature. Apple's first mice used a DE-9 connection carrying quadrature signals. The phase may be measured with a quadrature detector. Cotes formulas (like the midpoint rule or Simpson's rule) or Gaussian quadrature. The error of a Gaussian quadrature rule can be stated as follows .