wvd   Linux PC

PURPOSE ^

Wigner-Ville distribution

DESCRIPTION ^

 Wigner-Ville distribution

 Computes the wvd of the input signal. An analytic signal
 generator is called if the input signal is real. The supplied
 length of the analysis window defines whether the "true" wvd or
 a pseudo (windowed) wvd is computed. This version takes
 advantage of the reality of the wvd to increase calculation
 speed.

 Usage:

     tfd = wvd(signal, [lag_window_length] [,time_res] [, fft_length] )

 Parameters:

    signal

      Input one dimensional signal to be analysed. An analytic signal
      is required for this function, however, if signal is real, a
      default analytic transformer routine will be called from this
      function before computing tfd.

    lag_window_length

      This is the data window length and controls the size of
      the kernel used for analysis (lag_window_length must    be
      odd). The kernel used will be defined from -(lag_window_length+1)/2
      to +(lag_window_length+1)/2 in both time and lag dimensions.

    time_res

      The number of time samples to skip between successive slices.
      Default vaule is 1.

    fft_length

      Zero-padding at the FFT stage of the analysis may be specified by
      giving an fft_length larger than lag_window_length. If fft_length
      is not specified, or is smaller than the lag_window_length, then the
      next highest power of two above lag_window_length is    used. If
      fft_length is not a power of two, the next highest power of two is
      used.

     tfd

      The computed time-frequency distribution. size(tfd) will
      return [a, b], where a is the next largest power of two above
      fft_length, and b is floor(length(signal)/time_res) - 1.



  See Also: analyt, quadtfd

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