Patent ID: 8369809
Filing Date: 2013-02-05
Classification: H03F,H04B

Abstract:
1. A device for generating a crest factor reduced signal comprising: an interface configured to receive an input signal; a peak identifier configured to identify one or more peak regions of the input signal; a squelch level determiner configured to determine a reduction of the input signal near the one or more peak regions; a squelcher configured to reduce the one or more peak regions of the input signal as indicated by the squelch level determiner; an interface configured to output the crest factor reduced signal, wherein the crest factor reduced signal has a reduced dynamic range due to the reduction of the one or more peak regions of the input signal, the crest factor reduced signal has been filtered to reduce undesired frequency components by: calculating a difference between a squelched signal from the squelcher and the input signal, band-pass filtering the difference to generate a result, and summing the result with an input signal that has been delayed, wherein the peak identifier comprises: an absolute value processor configured to determine an absolute value of the input signal; a window function filter configured to determine a smoothed absolute value of the input signal; and a threshold pass processor configured to identify the one or more peak regions by identifying regions where the smoothed absolute value of the input signal is above a threshold, to set a threshold pass output signal equal to a threshold pass input signal when the threshold pass input signal is above a predetermined threshold value, and to set the threshold pass output signal to zero when the threshold pass input signal is below the predetermined threshold value.