Markov:

--------------------------------------------------------------------------
   Generate random output from a Gauss-Markov process. The 
   autocorrelation function for a Gauss-Markov process is

   sigma^2*exp(-abs(tau)/tCorr)

   Since version 1.
--------------------------------------------------------------------------
   Form:
   [x, tau] = Markov( sigma, tCorr, n, tSamp )
--------------------------------------------------------------------------

   ------
   Inputs
   ------
   sigma        (:)    Square root of mean squared value
   tCorr        (:)    Correlation time constant
   n            (1,1)  Number of samples
   tSamp        (1,1)  Sampling period

   -------
   Outputs
   -------
   x          (:,n)    Output
   tau          (n)    Time shifts

--------------------------------------------------------------------------