AMPLIFIER WITH FEEDFORWARD LOOPS FOR REJECTING NON-LINEAR DISTORTION

摘要

An amplifier with feedforward loops for rejecting non-linear distortion and control circuitry for such amplifier and employing a distortion compensation method. A signal from a dominant path is input into a synchronizing detector via an ALC circuit as a reference signal. Using this reference signal, an error signal output from a distortion rejection loop is subjected to synchronizing detection. An offset voltage of a mixer inside the synchronizing detector can be prevented from varying due to change in local level. Outputs from synchronizing detectors are used for control to optimize corresponding loops. As a pilot signal for a distortion detection loop can be eliminated, undesirable spurious effects due to such a pilot signal is avoided. The acquisition time of each of the loops can be shortened because an optimizing control using a step-by-step procedure under CPU control can be eliminated.