I would like to compute the CSD of two finite time series. Is this implemented in R. Spectrum can handle multivariate input, but computes the coherence and the phase, but not the cross spectral density. Are there any packages out there that can do what I am asking? thanks Stephen Sefick -- Let's not spend our time and resources thinking about things that are so little or so large that all they really do for us is puff us up and make us feel like gods. We are mammals, and have not exhausted the annoying little problems of being mammals. -K. Mullis