Crest factor reduction for signals with dynamic power and frequency distribution

摘要

A method to form a CFR cancellation filter for signals with dynamic power and frequency distribution by estimating the filter at the rate required by the input signal's dynamics. For mixed mode systems (for example CDMA and LTE) the CFR is computed for each stream, and combined to form the final filter.

主权项

1. A method of computing a Crest Factor Reduction (CFR) filter, comprising the steps of:
receiving an input signal; selecting a window of selectable length; computing a Fast Fourier Transform (FFT) on the input signal within the selected window; computing a magnitude square of the computed FFT results; computing an average of the magnitude squared using a selectable number of samples; computing a square root of the said averaged magnitude squared; computing an Inverse FFT of the said square root; normalizing the results of the Inverse FFT thus generating a CFR cancellation pulse; and applying the CFR cancellation pulse to the input signal.