Patent ID: 7672397
Filing Date: 2010-03-02
Classification: H03F

Abstract:
1. A method for producing a transmission signal, wherein an input signal to be amplified is fed to a power amplifier which outputs the signal as an amplified output signal, the method comprising: making a reproduction which allocates a pre-distortion input signal value to a value of the input signal; determining the corresponding pre-distortion value for the input signal via the reproduction; applying the pre-distortion value to the input signal and feeding a resulting pre-distorted input signal to the power amplifier; generating an envelope-curve signal by incoherently demodulating the amplified output signal; determining a crest factor from the envelope-curve signal; and adapting the reproduction if the determined crest factor is not in a predetermined range, without respect to delay in a feedback path, wherein adapting the reproduction comprises: adjusting the reproduction to allocate a new pre-distortion input signal value to the value of the input signal; determining the corresponding pre-distortion value for the input signal via the adjusted reproduction; applying the re-determined pre-distortion value to the input signal; re-generating an envelope-curve signal by incoherently demodulating the new amplified output signal; re-determining the crest factor from the re-generated envelope-curve signal; and repeating the steps of adjusting, applying the re-determined predistortion, re-generating, and re-determining until the determined crest factor is in the predetermined range.