Patent ID: 8542062

Claim:
A method for linearizing a power amplifier circuit having an input signal input, a power output signal output, a power amplifier and a linearizer module, the method comprising the steps of: extracting a feedback signal from the power amplifier output signal; down-converting the feedback radio frequency (RF) signal to a feedback intermediate frequency (IF) signal; filtering the feedback IF signal with a band-pass filter; analog/digital (AD) converting the filtered feedback IF signal into a feedback digital signal; converting the feedback digital signal into a frequency-domain using a fast-Fourier transform (FFT) on a block of n-samples to obtain a feedback-FFT (FB-FFT) block; converting the input base-band digital signal into a frequency-domain using an FFT on a block of n-samples to obtain an input feed forward-FFT (FF-FFT) block; dividing the input FF-FFT blocks with the FB-FFT blocks to obtain FFT correction samples blocks; averaging at least two blocks of FFT correction samples to obtain FFT correction coefficient values; applying the FFT correction coefficient values to a digital complex multiplier; converting an output of the multiplier from frequency domain into time domain with an inverse FFT module to obtain a corrected digital input signal; converting the corrected digital input signal to analog IF signal with a digital to analog converter to obtain a corrected IF input signal; applying the band-pass filter to the corrected IF input signal; up-converting the filtered corrected IF input signal to obtain a corrected RF input signal; and applying the corrected RF input signal to the power amplifier.