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IQ Data
A sinusoid with modulation can be decomposed into, or synthesized from, two Amplitude modulation, amplitude-modulated sinusoids that are in quadrature phase, i.e., with a Phase (waves), phase offset of one-quarter cycle (90 degrees or /2 radians). All three sinusoids have the same center frequency. The two amplitude-modulated sinusoids are known as the in-phase (I) and quadrature (Q) components, which describes their relationships with the amplitude- and phase-modulated carrier. Or in other words, it is possible to create an arbitrarily phase-shifted sine wave, by mixing together two sine waves that are 90° out of phase in different proportions. The implication is that the modulations in some signal can be treated separately from the carrier wave of the signal. This has extensive use in many radio and signal processing applications. #I/Q data, I/Q data is used to represent the modulations of some carrier, independent of that carrier's frequency. Orthogonality In vector anal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phase Quadrature
In physics and mathematics, the phase (symbol φ or ϕ) of a Wave (physics), wave or other periodic function F of some real number, 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 scale (ratio), scale that it varies by one full turn (geometry), turn as the variable t goes through each Period (physics), period (and F(t) goes through each complete cycle). It may be Measure (mathematics), measured in any angular unit such as degree (angle), degrees or radians, thus increasing by 360° or 2\pi as the variable t completes a full period. This convention is especially appropriate for a sinusoidal function, since its value at any argument t then can be expressed as \varphi(t), the sine of the phase, multiplied by some factor (the amplitude of the sinusoid). (The cosine may be used instead of sine, depending on where one considers each period to start.) Usually, whole turns are ignored when expres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
