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!-------------------------------------------------------------------------------
!
! This file is part of the WSPR application, Weak Signal Propogation Reporter
!
! File Name: ccf2.f90
! Description:
!
! Copyright (C) 2001-2014 Joseph Taylor, K1JT
! License: GPL-3+
!
! This program is free software; you can redistribute it and/or modify it under
! the terms of the GNU General Public License as published by the Free Software
! Foundation; either version 3 of the License, or (at your option) any later
! version.
!
! This program is distributed in the hope that it will be useful, but WITHOUT
! ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
! FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
! details.
!
! You should have received a copy of the GNU General Public License along with
! this program; if not, write to the Free Software Foundation, Inc., 51 Franklin
! Street, Fifth Floor, Boston, MA 02110-1301, USA.
!
!-------------------------------------------------------------------------------
subroutine ccf2(ss,nz,lag1,lag2,ccfbest,lagpk)
real ss(nz)
real pr(162)
logical first
! The WSPR pseudo-random sync pattern:
integer npr(162)
data npr/ &
1,1,0,0,0,0,0,0,1,0,0,0,1,1,1,0,0,0,1,0, &
0,1,0,1,1,1,1,0,0,0,0,0,0,0,1,0,0,1,0,1, &
0,0,0,0,0,0,1,0,1,1,0,0,1,1,0,1,0,0,0,1, &
1,0,1,0,0,0,0,1,1,0,1,0,1,0,1,0,1,0,0,1, &
0,0,1,0,1,1,0,0,0,1,1,0,1,0,1,0,0,0,1,0, &
0,0,0,0,1,0,0,1,0,0,1,1,1,0,1,1,0,0,1,1, &
0,1,0,0,0,1,1,1,0,0,0,0,0,1,0,1,0,0,1,1, &
0,0,0,0,0,0,0,1,1,0,1,0,1,1,0,0,0,1,1,0, &
0,0/
data first/.true./
save
if(first) then
nsym=162
do i=1,nsym
pr(i)=2*npr(i)-1
enddo
endif
ccfbest=0.
do lag=lag1,lag2
x=0.
do i=1,nsym
j=16*i + lag
if(j.ge.1 .and. j.le.nz) x=x+ss(j)*pr(i)
enddo
if(x.gt.ccfbest) then
ccfbest=x
lagpk=lag
endif
enddo
return
end subroutine ccf2
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