Phasing and/or Clipping Tones for a Peak Amplitude Limitation.

摘要

Minimization of the peak value of the envelope (crest factor) of a narrowband waveform composed of N equal-amplitude equispaced sine waves,by means of phasing the individual tones,is investigated for a wide range of values of N. The method of solution is a numerical one,making judicious use of random search,gradient search,and the Fast Fourier Transform. Some analytic results for a simple quadratic-phased technique are presented and augmented via numerical techniques to form a possible basis for synthesizing tone sets with acceptable peak envelope behavior for large N. The dependence of the minimum peak amplitude on modified quadratic phases,irregularly spaced tones,and clipping are also investigated.