mirror of https://github.com/saitohirga/WSJT-X.git
46 lines
1.1 KiB
Fortran
46 lines
1.1 KiB
Fortran
subroutine ccf2(ss,nz,nflip,ccfbest,lagpk)
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! parameter (LAGMAX=60)
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parameter (LAGMAX=200)
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real ss(nz)
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real ccf(-LAGMAX:LAGMAX)
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integer npr(126)
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! The JT65 pseudo-random sync pattern:
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data npr/ &
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1,0,0,1,1,0,0,0,1,1,1,1,1,1,0,1,0,1,0,0, &
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0,1,0,1,1,0,0,1,0,0,0,1,1,1,0,0,1,1,1,1, &
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0,1,1,0,1,1,1,1,0,0,0,1,1,0,1,0,1,0,1,1, &
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0,0,1,1,0,1,0,1,0,1,0,0,1,0,0,0,0,0,0,1, &
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1,0,0,0,0,0,0,0,1,1,0,1,0,0,1,0,1,1,0,1, &
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0,1,0,1,0,0,1,1,0,0,1,0,0,1,0,0,0,0,1,1, &
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1,1,1,1,1,1/
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save
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ccfbest=0.
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lag1=-LAGMAX
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lag2=LAGMAX
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do lag=lag1,lag2
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s0=0.
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s1=0.
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do i=1,126
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j=2*(8*i + 43) + lag
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if(j.ge.1 .and. j.le.nz-8) then
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x=ss(j)+ss(j+8) !Add two half-symbol contributions
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if(npr(i).eq.0) then
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s0=s0 + x
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else
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s1=s1 + x
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endif
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endif
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enddo
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ccf(lag)=nflip*(s1-s0)
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if(ccf(lag).gt.ccfbest) then
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ccfbest=ccf(lag)
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lagpk=lag
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endif
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enddo
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return
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end subroutine ccf2
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