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Parameters, alphabetically:
----------  --------------
addwb     double    fillen    fno       lno       lprint
paddwb    pdist     prewhi    seats     sedts     vel

Document Date:  19 July 2010
  July 2010 - Add lprint 8 to print the filter points.

Process DECON designs and applies a least squares prediction error 
filter.  Linear prediction deconvolution reduces periodic events such as
bubble pulses, ring, or even long period multiples.

Procedurally, an autocorrelation of the design window is taken and an
inverse filter is designed so that the autocorrelation of the same 
window after decon results is a spike followed by zeroes.  DECON uses
the classic "Weiner-Levinson" method.  Les Hatton's "Seismic Data
Processing", Blackwell Scientific Publications, has an excellent section
on Weiner filtering.

Time varying decon is performed by applying different filters to 
different parts of the trace.  The different parts of the trace are 
called windows.  The portion of the trace between windows are merged by
ramping (linear).  The merge zone thus contains data that has been 
filtered by different filters and then added together after being ramped.
               F1            F2            F3
          ..........     ..........     ..........
                    .   .          .   .
                     . .            . .
                      .              .
                     . .            . .
                    .   .          .   .

Up to 5 windows may be given, and may be spatially varied by shot or 
by hanging the windows on the water bottom.

All parameters that remain constant for a set of shots (rps) may be 
described in a parameter set FNO to LNO.  Windows between two parameter
sets are calculated by linearly interpolating between the LNO of one set
and the FNO of the next set.

Each parameter list must be terminated with the word END.  The entire 
set of decon parameters must be terminated by the word END.

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

SEDTS  - Start-end time pairs defining the design windows.  Times
         are in seconds and may be negative when hanging the windows
         from the water bottom.  A maximum of 5 windows may be given.
         The window length should be many times the length of the
         period being removed; the period must be on the autocor-
         relation.  Parameter SEATS must be given when doing multi-
         window decon.

VEL    - The velocity to use to 'move-in' each design window time.
         Move-in is useful for describing window times that need 
         to vary according to the shot-receiver distance, as in 
         following a reflector on a record before nmo.  Each
         design window time will be determined from the equation:
         t=sqrt(t0*t0+x*x/(vel*vel)), where t0 is the normal
         incidence two way travel time, and x is the shot to 
         receiver distance of the trace described via PROCESS GEOM.

FILLEN - The length of each filter in seconds.  Up to 5 filter lengths
         may be given.  The filter length must be sufficient to include
         the period being removed.
         Preset=.160 .160. .160 .160 .160

PREWHI - The percentage prewhitening to add before filter design.
         A high level of prewhitening reduces the effectiveness of
         the filter.  Some level of prewhitening is needed in
         order for the filter to be stable.  Prewhitening is like
         performing a bandpass filter before decon.

ADDWB  - When given a value of YES, the windows given via SEDTS
         will be added to the water bottom time of the trace.
         (Water bottom times may be entered via PROCESS WBT).

SEATS  - Start-end time pairs defining the application windows.  Times
         are in seconds and may be negative when hanging the windows
         from the water bottom.  A maximum of 5 windows may be given.
         There must be the same number of design windows (SEDTS) as
         application windows (SEATS).
         Preset = whole trace

PDIST  - The prediction distance, in seconds.  The prediction 
         distance is the time delay of the event to be removed.
         Preset=3*sample interval. 
         e.g. pdist .15 (For water bottom multiple)

PADDWB - When given a value of yes, the water bottom time will be 
         added to the value of PDIST on each trace.
         Preset=no.  e.g. paddwb yes

DOUBLE - When given a value of yes, the correlations and 
         convolution are performed in DOUBLE PRECISION.  THE USE 
         but might make the decon work better especially if long 
         windows are used.
         Preset = no.    e.g.  yes

FNO    - The first shot (or rp) to apply the decon to.  
         Shot (rp) numbers must increase monotonically.

LNO    - The last shot (rp) number to apply the decon to.  Lno 
         must be larger than FNO in each list and must increase
         list to list.

LPRINT - Print switch.
       = 2, The edit phase parameters are printed.
       = 4, The exectute phase parameters are printed.
       = 8, The computed decon filter points are printed.


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

PREDIC - The prediction distance, in samples.  Same as PDIST but
         in samples rather than time.  If both PREDIC and PDIST are
         given, PDIST is used.

Written and copyrighted by:
Paul Henkart, Scripps Institution of Oceanography, June 1980
All rights reserved.
Go to the list of seismic processes.      Go to SIOSEIS introduction.