In the figure, A 1 is the main amplifier and A2 is the error amplifier. The input signal is divided into two paths by the power divider DC 1, one path is amplified by the main amplifier, and part of the amplified output signal is attenuated and phase-shifted by the coupler DC2 and sent to the power combiner DC3, while the other path is also sent to DC3 after being delayed by the power divider DC 1. As long as it is properly adjusted, the two signals cancel each other in DC3, and only the distortion component produced by A 1 is excluded by DC3. The distortion component is amplified by A2 and then transmitted to DC4 through attenuation and phase shift. The signal output by A 1 is also sent to DC4 after delay. As long as it is properly adjusted, these two signals will also cancel each other in DC4, and DC4 will output a pure signal with the distortion component cancelled. This feedforward technique can improve the distortion by 20dB to 30dB.