An Etymological Dictionary of Astronomy and Astrophysics
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1) Denoting a device or method of combining two → electromagnetic waves of different → frequency (a locally generated wave and an incoming wave) in a → nonlinear device to produce two frequencies which are equal to the → sum and → difference of the first two. The phenomenon is the counterpart of → beats produced by → sound waves. For example, heterodyning a 100-kHz and a 10-kHz signal will produce a 110-KHz and a 90-kHz signal. See also → homodyne.
2) The term heterodyne is often loosely used instead of → superheterodyne in the radio frequency field.

Heterodyne, from → hetero- + -dyne, from Gk. dynamics→ dynamics; → receiver.

An → interferometer using a technique that involves introducing a small → frequency shift between the optical frequencies of the two interfering light beams. This results in an intensity modulation at the → beat frequency of the two beams for any given point of the → interference pattern. A convenient way of introducing such a frequency shift is by means of an acousto-optic modulator.

→ heterodyne; → interferometer.

→ superheterodyne receiver.

→ heterodyne; → receiver.

→ superheterodyne technique.

→ heterodyne; → technique.

A radio receiver which uses the → superheterodyne technique.

→ super-; → heterodyne; → receiver.

The technique used in a radio receiver in which the frequency of an incoming signal is changed by adding it to a signal generated within the receiver to produce fluctuations or beats of a frequency equal to the difference between the two signals. See also → mixer.

→ superheterodyne receiver; → technique.