Patent ID: 6240141
Filing Date: 2001-05-29
Classification: H04L

Abstract:
A peak-reducing Inverse Fourier transformer comprising:an input array in a frequency domain, the input array containing multiple frequency bins;an output array in a time domain, the output array containing data points representing voltages at different time points;an intermediate array containing intermediate values;a first transformer, receiving the input array, for generating the intermediate array by partially Inverse Fourier transforming the input array;a second transformer, receiving the intermediate array, for generating the output array by partially inverse Fourier transforming the intermediate array;a peak searcher, coupled to the output array, for searching the data points in the output array for voltages falling outside a clipping threshold, the peak searcher for identifying a peak location of an over-threshold peak in the output array; anda subset sign inverter, coupled to the peak searcher, for inverting signs of subsets of original intermediate values in the intermediate array to generate sign-inverted intermediate values, wherein when the sign-inverted intermediate values replace the original intermediate values in the intermediate array, the over-threshold peak in the output array is reduced in voltage and is within the clipping threshold,whereby the over-threshold peak is reduced by sign-inversion of the subsets of the original intermediate values.