bilinear_tfsa

PURPOSE ^

GENERATE BILINEAR TIME-FREQUENCY TRANSFORMATIONS

DESCRIPTION ^

 GENERATE BILINEAR TIME-FREQUENCY TRANSFORMATIONS

 BILINEAR TRANSFORMATIONS transform the time domain signal (the
 variable INPUT SIGNAL) to an output quadratic time-frequency
 distribution (the variable OUTPUT TIME-FREQUENCY ARRAY)

 There are many different types of quadratic time-frequency distributions
 that can be specified:
   
   (i)     Wigner-Ville Distribution (WVD)
   (ii)    Spectrogram (SPECX) 
   (iii)   S_Method (S_Method)
   (iv)    Smoothed Wigner-Ville (SMOOTHED)
   (v)     Rihaczek-Margenau-Hill (RM)
   (vi)    Choi-Williams (CW)
   (vii)   Born-Jordon (BJ)
   (viii)  Zhao-Atles-Marks (ZAM)
   (ix)    Cross-Wigner-Ville Distribution (XWVD)
   (x)     B-distribution (B)
   (xi)    Modified B-distribution (MB)
   (xii)   Extended Modified B-distribution (EMB)
   (xiii)  Compact kernel Distribution(CKD)
   (xiv)   Multidirectional Kenel Distribution (MDD)


   and also an Ambiguity Function with transforms the signal into the
   dopple-lag domain.

   The various parameters associated with the distributions are as follows:

   TIME-FREQUENCY ARRAY (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.

   INPUT 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.

   TIME RESOLUTION

      The number of time samples to skip between successive slices.

   LAG WINDOW LENGTH

      This is the lag window length and controls the size of the
      signal kernel (or instantaneous autocorrelation function) 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.

   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.

    KERNEL OPTIONS

      Each time-frequency distribution has various options that can
      be adjusted to produce the desired tfd.



  See Also:  quadtfd, analyt

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