Name

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      ENVELOPE

Purpose

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      Return the min/max envelope of a time series.

Category

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Calling Sequence

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      envelope, y, w, mn, mx, ind

Inputs

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      y = time series signal. in
      w = window width in samples. in

Keyword Parameters

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Keywords

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        INMN=inmn Returned array of minima indices.
        INMX=inmx Returned array of maxima indices.

Outputs

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      mn = array of mins in each window. out
      mx = array of maxes in each window. out
      ind = array of window midpoint indices. out

Common Blocks

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Notes

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      Notes: data type of mn and mx are the same as
        input array y.
        To overplot envelope do:
          oplot,ind,mn & oplot,ind,mx
        To polyfill the envelope do:
          polyfill, [ind,reverse(ind)],[mn,reverse(mx)]
          May not fill ends.
        Some minima or maxima may fall outside the envelope
        depending on the window width.

Modification History

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      R. Sterner, 19 Sep, 1991
      R. Sterner, 2010 May 04 --- Converted arrays from () to [].
      R. Sterner, 2012 Mar 20 --- Added INMN=inmn, INMX=inmx.
  Copyright (C) 1991, 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.