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                        PROCESS AVENOR
                        ------- ------

Parameters, alphabetically:
addwb     fno       hold      levs      lno       lprint
sets      vel

Document Date: 12 October 2002

     Process AVENOR normalizes every trace window to a user described
window level by calculating and appling a multiplier so that the average
amplitude within the window is at a certain level.  The resulting traces
will be more uniform in amplitude.

      AVENOR finds a window multiplier by dividing the user's window 
level by the average absolute value of the window.  The multiplier is 
held constant for all data before the center of the first window, is 
linearly interpolated between window centers and held constant for all
data after the center of the last window.  Thus, defining only one
window results in a constant multiplier for each trace.

     Up to 4 windows may be given, each with a different window level,
and may be  spatially varied by shot or rp 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 lno of one set and
FNO of the next set.

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

     A null set of AVENOR parameters must be given if all parameters to
be used are the presets.  e.g. avenor
                                      end
                                end

THE PARAMETER DICTIONARY
--- --------- ----------

SETS   - Start-end time pairs defining the windows.  Times are in
         seconds and may be negative when hanging the windows from the
         water bottom.  A maximum of 4 windows may be given.  The
         windows may not overlap.
         Preset= delay to last time.   sets 0 3 3 6

LEVS   - The amplitude level of each window described by the sets.  Each
         window may have a different level.  A negative level reverses
         the polarity.   Up to 4 levels may be given.
         Preset= 10000. 10000. 10000. 10000.

FNO    - The first shot (or rp) to apply normalization to.  Shot (rp)
         numbers must increase monotonically.
         Preset=1

LNO    - The last shot (rp) number to apply normalization to.  LNO must
         be larger than FNO in each list and must increase from list to
         list.
         Default=fno

VEL    - The velocity to use to 'move-in' each 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 window time is determined from the
         equation:
         t=sqrt(t0*t0+x*x/(vel*vel)), where t0 is the two way travel
         time, and x is the shot to receiver distance of the trace
         described via PROCESS GEOM.
         Preset=0.

ADDWB  - When given a value of YES, the water bottom time will be
         added to all window times.  (Water bottom times may be
         entered via PROCESS WBT).
         Preset=no

HOLD   - New multipliers are calculated on the first HOLD traces.
         The multiplier from the last of these traces in then
         used on all successive traces.
         Preset = 0

LPRINT - The normal debug parameter for values of 1 and 2.
       =4, The average absolute value for each window is printed.

END    - Terminates each parameter list.


Written and copyrighted by:
Paul Henkart, Scripps Institution of Oceanography, May 1980
ALL RIGHTS RESERVED
Go to the list of seismic processes.      Go to SIOSEIS introduction.