Stewart L Cummings

US Patent:

52277364, Jul 13, 1993

Filed:

May 18, 1992

Appl. No.:

7/884367

Inventors:

Mark E. Tucker - San Diego CA
Stewart L. Cummings - Oceanside CA

Assignee:

Tacan Corporation - Carlsbad CA

International Classification:

H03F 132

US Classification:

330149

Abstract:

The second-order predistorter comprises two RF amplifiers and three 180. degree. hybrid combiner/splitters. The RF sinusoidal input is split into two separate signals which have equal amplitudes but are 180. degree. out of phase. Each of these signals is fed into separate moderately linear amplifiers, the output of each being composed only of the amplified input signal and second-order distortion components produced by the amplifiers' nonlinearities. The output signal from each amplifier is combined with the other in a second combiner/splitter to produce two different outputs consisting of the sum and difference of the amplified signals. The difference signal consists only of the desired signal, and the sum signal consists of only the second-order distortion terms. The sum and difference signals are recombined in a third combiner/splitter to form a composite signal which is input into the device to be linearized. The output signal of the final hybrid combiner/splitter is taken from its sum or its difference port, depending on the desired relative phase between the amplified signals.