sentences:  It can be expressed in terms of repeated Fourier transforms, and its discrete analogue can be computed efficiently using a fast Fourier transform algorithm.The transform uses a family of "harmonic" wavelets indexed by two integers "j" (the "level" or "order") and "k" (the "translation"), given by formula_1, where
  
  These functions are orthogonal, and their Fourier transforms are a square window function (constant in a certain octave band and zero elsewhere).In particular, they satisfy