[teqc] change in decimation algorithm

Lou Estey lou at unavco.org
Mon Nov 28 14:36:34 MST 2005


All,

A change has been made in the teqc decimation algorithm which would affect
discussions made in http://ls.unavco.org/pipermail/teqc/2004/000066.html
(last in thread) and http://ls.unavco.org/pipermail/teqc/2005/000112.html
(first in thread).  If it works (and it appears to on nasty sample data),
the use of -O.int to specify the original sample interval would not be
needed (usually) unless the original interval were less than 0.002 sec (i.e.
faster than 500-Hz data) -- essentially eliminating the need to specify the
original sample interval with -O.int under normal circumstances.

The only known case where -O.int would still be needed would be where
the epochs are significantly "off" from the nominal epoch.  E.g. where
the 1-sec epochs are (from real data!):

  97  2 28 18 54 26.8338366
  97  2 28 18 54 27.8338423
  97  2 28 18 54 28.8338481
  97  2 28 18 54 29.8338538
  97  2 28 18 54 30.8338594
  97  2 28 18 54 31.8338648

one would need to use, say, `-O.dec 5 -O.int 1` in order to decimate to
the nearest 5-sec epochs:

  97  2 28 18 54 29.8338538
  97  2 28 18 54 34.8338822
  97  2 28 18 54 39.8339107

This won't be available on-line until we do a bit more testing in-house.

cheers,
--lou

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Louis H. Estey, Ph.D.              office:  [+001] 303-381-7456
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                                                -- Leon Lederman
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