rfic technique-Amplitude and phase correction loop
Modulating the voltage input to the PA can create noise or other distortions in the amplified signal. To eliminate this, the best technique can be used utilizes a closed-loop correction system containing very high bandwidth amplitude and phase loops to intelligently sense the RF signal amplitude and phase at the input and output of the PA, and applies a correcting signal to the RF signal path as it passes through the transceiver circuitry on its way to the input of the PA. This cleans up any distortions introduced by the modulated voltage, the PA, surrounding circuitry, or operating conditions. The closed loop circuitry is designed to use very little power, so the added energy necessary to implement this technology is negligible.