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RSPEC

RSPEC

Name


      RSPEC

Purpose


      Compute an ensemble averaged frequency spectrum of real data.

Category


Calling Sequence


      sxx = rspec(x,n,sr,[freq])

Inputs


      x = input signal. in
        If x has too few points, -1 is returned.
      n = number of points to use in each transform in
        May be arbitrary.
      sr = sample rate in Hz (Def=1 Hz) in
        Needed to get actual units.

Keyword Parameters


Keywords


        OVERLAP=novr number of points to overlap spectra (Def=0).
        ZEROPAD=zlen length to zero pad out to (def=no 0 pad).
        N_ENSEMBLE=n returned # spectra ensemble averaged.
        /ACCUMUALTE means accumulate the spectra, don't average.
        /NOTES lists some additional comments.

Outputs


      sxx = spectral density in units of x^2/Hz. out
        First value is DC, last is Nyquist.
      freq = optionally output frequency array. out

Common Blocks


      rspec_com

Notes


      Notes: Restricted to one dimensional data only.

Reference


Modification History


      B. L. Gotwols Oct. 11, 1990.
      R. E. Sterner 7 Aug, 1991 --- return only 1-side (symetric)
      R. D. Chapman 2 Dec, 1992 --- fixed common blk reference to hannratio
      R. E. Sterner 1 Mar, 1993 --- tested for ntimes eq 0 sooner.
      R. Sterner, 19 May, 1993 --- forced correct data types.
      Rewrote from xspec.pro to get overlap.
      R. Sterner, 23 Nov, 1993 --- Added /ACCUMULATE keyword
      R. Sterner, 1994 Nov 10 --- Added ZEROPAD keyword.
  Copyright (C) 1990, Johns Hopkins University/Applied Physics Laboratory
  This software may be used, copied, or redistributed as long as it is not
  sold and this copyright notice is reproduced on each copy made. This
  routine is provided as is without any express or implied warranties
  whatsoever. Other limitations apply as described in the file disclaimer.txt.



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