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*DECK DETFIL
SUBROUTINE DETFIL(Y,X,XL,TC,DT,N)
*
*----------------------------------------------------------------------
*
*Purpose:
* Filters the n values of x vector for TC seconds.
* Formulations are taken from the expression of the different
* equation of a filter with a linear variation of x in DT time
* step.
*
*Author(s):
* xxx
*
*Parameters:
* Y real variables Y(I) at previous time
* X real variables to filtered
* XL real variables X(I) at previous time
* TC filter time constant
* DT time step between two calculations
* N dimension of the vectors X,XL,Y
*
*--------------------------------------------------------------------
*
IMPLICIT NONE
INTEGER N,I
REAL Y(N),X(N),XL(N),TC,DT,AA,A,B,C
*
* COMPUTE PONDERATION FACTORS FOR Y,X ET XL
*
AA = - DT / TC
A = EXP ( AA )
B = 1. - A
C = 1. - B * TC/DT
*
* COMPUTE NEW Y
*
DO 10 I=1,N
*
Y(I) = A * Y(I) + ( B - C ) * XL(I) + C * X(I)
XL(I) = X(I)
*
10 CONTINUE
RETURN
END
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