Patent ID: 6326845
Filing Date: 2001-12-04
Classification: H03F

Abstract:
A feedforward amplifier comprising:a power divider which divides an input signal into first and second divided signals;a first vector adjuster which adjusts amplitude and phase of the first divided signal;a main amplifier for amplifying an adjusted output of said first vector adjuster to provide an amplified signal;a first delay circuit which delays the second divided signal, said first delay circuit including a first distortion suppressing band-pass filter;a directional coupler which receives the amplified signal and has a main output port and a coupler output port;a first power combiner which combines a signal from said coupler output port and a first delayed signal from said first delay circuit;a second delay circuit which delays a signal from said main output port, said second delay circuit including a second distortion suppressing band-pass filter;a second vector adjuster which adjusts amplitude and phase of an output signal of said first power combiner;an error amplifier which amplifies an output signal of said second vector adjuster; anda second power combiner which combines an output signal of said second delay circuit with an output signal of said error amplifier, to provide a combined signal;said first vector adjuster and said first delay circuit adjusted to cancel objective signal components leaving only distortion components;said second vector adjuster and said second delay circuit adjusted to cancel distortion components leaving only objective signal components; andsaid first and second filters reducing distortion components of the input signal.