correlation receiver

correlation receiver

A radio-astronomy receiver in which either the noise power from a single antenna is split and multiplied with itself or the noise power from the two arms of an interferometer (see radio telescope) are multiplied together. Signals that are uncorrelated (completely unrelated) give an output whose average value is zero when multiplied together. Correlated signals, however, produce components near zero frequency that give a steady deflection in the output of the multiplier. In addition to their use in radio interferometry, correlation receivers are also used to reduce the effect of interference and of changes in the gain and other parameters of the system. See also phase-switching interferometer.