Automatic frequency control: Difference between revisions

Revision as of 08:11, 23 October 2020

Revision as of 06:21, 3 March 2021

Line 8:

Assuming that a receiver is nearly tuned to the desired frequency, the AFC [[electrical network|circuit]] in the receiver develops an error [[voltage]] proportional to the degree to which the receiver is mistuned. This error voltage is then [[Feedback|fed back]] to the tuning circuit in such a way that the tuning error is reduced. In most [[frequency modulation]] (FM) detectors, an error voltage of this type is easily available. See [[Negative feedback]].

AFC was mainly used in radios and television sets around the mid-20th century. In the 1970s, receivers began to be designed using [[frequency synthesizer]] circuits, which synthesized the receiver's input frequency from a [[crystal oscillator]] using the vibrations of an ultra-stable [[crystal oscillator|quartz crystal]]. These maintained sufficiently stable frequencies that AFC'sAFCs were no longer needed.

== See also ==