2018-02-08 21:28:33 -05:00
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subroutine ccf2(ss,nz,nflip,ccfbest,xlagpk)
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2018-08-05 11:33:30 -04:00
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! parameter (LAGMIN=-86,LAGMAX=258)
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parameter (LAGMIN=-112,LAGMAX=258) ! Look for DT from -3.6s to +5.0s
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2018-02-08 21:28:33 -05:00
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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=LAGMIN
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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=16*(i-1)+1 + lag
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if(j.ge.1 .and. j.le.nz-8) then
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x=ss(j)
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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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xlagpk=lagpk
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endif
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enddo
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if( lagpk.gt.-LAGMAX .and. lagpk.lt.LAGMAX) then
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call peakup(ccf(lagpk-1),ccf(lagpk),ccf(lagpk+1),dx)
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xlagpk=lagpk+dx
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endif
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return
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end subroutine ccf2
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