Function: fftanalytic
FFTANALYTIC Compute analytic representation
  Usage:  z = fftanalytic(f);
          z = fftanalytic(f,L);
          z = fftanalytic(f,L,dim);

  Input parameters:
        f     : Input data.
        L     : Extend or truncate f to this length.
        dim   : Dimension to along which to apply the computations.
  Output parameters:
        z     : Analytic signal.

  FFTANALYTIC(f) computes the analytic representation of a 
  real-valued signal f. The analytic representation is computed 
  through the FFT of f. The computations are done along the first 
  non-singleton dimension. 

  FFTANALYTIC(f,L) acts as before but f is padded with zeros or 
  truncated to length L.

  FFTANALYTIC(f,L,dim) in addition allows specifying the dimension 
  along which the computation should be done.

  The real part of the analytic representation z equals the signal 
  f and the imaginary part is the Hilbert transform of f. 

  The instananeous amplitude (a Hilbert envelope) of the signal f can 
  be computed as:

    abs(fftanalytic(f));

  The instantaneous phase of the function f can be computed as:

    angle(fftanalytic(f));

Url: http://ltfat.github.io/doc/fourier/fftanalytic.html

Package: ltfat