Patent ID: 8649471

Claim:
An apparatus for applying a crest factor reduction to a signal, comprising: a peak detector module configured to identify peaks of an oversampled digital signal that exceed a crest factor reduction threshold; a correction waveform generator configured to generate a correction waveform corresponding to a sequence of correction pulses for respective peaks of the oversampled digital signal; a delta-sigma modulator configured to receive the oversampled digital signal at a signal input and the correction waveform at an error input and to apply the correction waveform to the oversampled digital signal to generate an oversampled digital output signal with peaks below the crest factor reduction threshold, wherein the delta-signal modulator causes a majority of the energy of the correction waveform in the oversampled digital output signal to fall outside a frequency band of the oversampled digital signal; a low pass filter configured to filter the oversampled digital output signal to remove energy outside the frequency band of the oversampled digital signal such that noise introduced into the oversampled digital output signal by the correction waveform is reduced; and a down-sampling module configured to perform down sampling on the oversampled digital output signal to produce a digital output signal with a lower sampling rate than the oversampled digital output signal.