Patent ID: 8498322

Claim:
A method for reducing undesired emissions from a power amplifier in a communications transmitter, the method comprising: using a feed-forward circuit, subtracting all or part of a desired transmitter-signal component from a first sampled signal coupled from the power amplifier's output signal path, to create a first error signal; injecting a first spread-spectrum pilot signal into the power amplifier's output signal path and into the first error signal, wherein the first spread-spectrum pilot signal occupies a first bandwidth at least partially overlapping a receiver band; adding the first error signal to an interference-carrying signal to form a reduced-interference signal, wherein the interference-carrying signal is in the power amplifier's output signal path or is coupled to the power amplifier's output signal path; measuring the first spread-spectrum pilot signal in the reduced-interference signal; and adjusting at least one parameter of the first error signal or the power amplifier output signal, based on the measuring of the first spread-spectrum pilot signal, to reduce the presence of the first error signal in the reduced-interference signal.