Synopsis
		sftimefreq < time.rsf > timefreq.rsf mask=mask.rsf nw= dw= w0=0. rect=10 niter=100 phase=n

Parameters
		float dw= f requency step   string mask= auxiliary input file name   int niter=100 number of inversion iterations   int nw= number of frequencies   bool phase=n [y/n] output phase instead of amplitude   int rect=10 smoothing radius   float w0=0. first frequency