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                       PROCESS RESAMP

Document date: 17 July 2008
Modifications: 17 July 2008 - Remove parameter TYPE.
                            - Default to using time domain interpolation.
                            - Rewrite the user documentation.

PROCESS RESAMP resamples the seismic trace from one sample interval to
another by doing a polynomial interpolation in the time domain.

This process is useful for converting data that is recorded at "not
nice" sample rates such as data are recorded with 128 samples per 
second which is a sample interval of .0078125 seconds per sample.

Many "high res" seismic systems oversample the data while digitizing
so that processing can be done in the frequency domain.  The data
are resampled in the frequency domain at a sample rate that is not
an integer sample interval in the time domain.  Most chirp systems
function this way so that the matched filter (correlation) is done 
in the frequency domain.

The SEG-Y format specifies the sample spacing as a sample interval,
not a sample rate.  The SEG-Y sample interval must be a 16 bit integer
and is expressed in microseconds (thousandth of a millisecond.)

--------- ----------

NEWSI  - The output sample interval, in seconds.
         REQUIRED.            e.g.   newsi  .004

ORDER  - The order of the interpolation when using type 2 interpolation.
         According to "Numerical Recipes": "We enthusiastically endorse
         interpolations with 3 or 4 points, we are perhaps tolerant of
         5 or 6; but we rarely go higher".
         Preset = 4   limits   1 < order < 7        e.g.   order 3

Copyright (C) 1993 The Regents of the University of California
Go to the list of seismic processes.      Go to SIOSEIS introduction.