Patent ID: 7376201

Claim:
A system for reducing a crest factor of a multi-carrier input signal including at least one carrier, the system comprising: a large signal extraction module for receiving the input signal and the magnitude of the input signal to extract a large signal greater than a predetermined threshold θ; a large signal transformation module for convening the extracted large signal to a monotonically increasing concave function; a large signal filtering module for filtering the large signal transformed by the large signal transformation module to pass a predetermined band of the large signal; delay means for shifting the phase of the input signal; and a combiner for combining the signal output from the large signal filtering module with the input signal whose phase has been shifted by the delay means to reduce the crest factor of the input signal, wherein said large signal extraction module extracts the large signal through the following equation d ( n )=0, if | s ( n )|≦θ=(| s ( n )−θ) s ( n ), if | s ( n )|>θ (Here, | s(n)| is the magnitude of s(n)), wherein d(n) is the large signal, s(n) is the input signal, θ is the predetermined threshold and n is a time sequence.