sentences:  The method of time-frequency reassignment
  is a technique for refocussing time-frequency data in a blurred representation like the spectrogram by mapping the
  data to time-frequency coordinates that are nearer to the
  true region of support of the analyzed signal.One of the best-known time-frequency representations is the
  spectrogram, defined as the squared magnitude of the
  short-time Fourier transform.Though the short-time phase
  spectrum is known to contain important temporal information
  about the signal, this information is difficult to
  interpret, so typically, only the short-time magnitude
  spectrum is considered in short-time spectral analysis.