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https://github.com/saitohirga/WSJT-X.git
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de3e975b98
2. ft8d is now a bare-bones multi-decoder. 3. wsjt-x now includes the bare-bones multi-decoder for FT8. git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@7729 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
92 lines
1.9 KiB
Fortran
92 lines
1.9 KiB
Fortran
subroutine sync8(iwave,s,candidate,ncand)
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include 'ft8_params.f90'
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parameter (JZ=20)
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complex cx(0:NH1)
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real s(NH1,NHSYM)
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real savg(NH1)
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real x(NFFT1)
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real sync2d(NH1,-JZ:JZ)
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real red(NH1)
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real candidate(3,100)
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integer*2 iwave(NMAX)
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integer jpeak(NH1)
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integer indx(NH1)
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integer ii(1)
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integer icos7(0:6)
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data icos7/2,5,6,0,4,1,3/ !Costas 7x7 tone pattern
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equivalence (x,cx)
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! Compute symbol spectra at half-symbol steps.
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savg=0.
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istep=NSPS/2
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tstep=istep/12000.0
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df=12000.0/NFFT1
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fac=1.0/300.0
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do j=1,NHSYM
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ia=(j-1)*istep + 1
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ib=ia+NSPS-1
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x(1:NSPS)=fac*iwave(ia:ib)
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x(NSPS+1:)=0.
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call four2a(x,NFFT1,1,-1,0) !r2c FFT
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do i=1,NH1
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s(i,j)=real(cx(i))**2 + aimag(cx(i))**2
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enddo
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savg=savg + s(1:NH1,j)
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enddo
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ia=nint(200.0/df)
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ib=nint(4000.0/df)
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savg=savg/NHSYM
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do i=ia,ib
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do j=-JZ,JZ
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t=0.
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do n=0,6
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k=j+2*n
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if(k.ge.1) t=t + s(i+2*icos7(n),k)
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t=t + s(i+2*icos7(n),k+72)
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if(k+144.le.NHSYM) t=t + s(i+2*icos7(n),k+144)
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enddo
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sync2d(i,j)=t
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enddo
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enddo
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red=0.
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do i=ia,ib
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ii=maxloc(sync2d(i,-JZ:JZ)) - 1 - JZ
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j0=ii(1)
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jpeak(i)=j0
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red(i)=sync2d(i,j0)
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enddo
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iz=ib-ia+1
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call indexx(red(ia:ib),iz,indx)
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ibase=indx(nint(0.40*iz)) - 1 + ia
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base=red(ibase)
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red=red/base
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candidate=0.
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k=0
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do i=1,100
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n=ia + indx(iz+1-i) - 1
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if(red(n).lt.2.0) exit
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do j=1,k !Eliminate near-dupe freqs
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f=n*df
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if(abs(f-candidate(1,j)).lt.3.0) go to 10
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enddo
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k=k+1
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candidate(1,k)=n*df
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candidate(2,k)=(jpeak(n)-1)*tstep
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candidate(3,k)=red(n)
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! write(*,3024) k,candidate(1:3,k)
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!3024 format(i3,3f10.2)
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10 continue
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enddo
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ncand=k
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fac=20.0/maxval(s)
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s=fac*s
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return
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end subroutine sync8
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