    means use tapers, use=anything other than 1 means do not use the
       multitaper method. If use=1, then tapers2spec controls the
       smoothing for the second Fourier transform. Otherwise, a direct
       Fourier transform is computed.
       params: structure with fields tapers, pad, Fs, fpass, err, trialave
       - optional
           tapers : precalculated tapers from dpss or in the one of the following
                    forms: 
                    (1) A numeric vector [TW K] where TW 