mirror of https://github.com/saitohirga/WSJT-X.git
33 lines
709 B
Fortran
33 lines
709 B
Fortran
subroutine peakdf9(c0,npts8,nsps8,istart,foffset,idfpk)
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complex c0(0:npts8-1)
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complex zsum
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include 'jt9sync.f90'
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twopi=8.0*atan(1.0)
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df=1500.0/nsps8
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smax=0.
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do idf=-5,5
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f0=foffset + 0.1*df*idf
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dphi=twopi*f0/1500.0
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sum=0.
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do j=1,16
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i1=(ii(j)-1)*nsps8 + istart
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phi=0.
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zsum=0.
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do i=i1,i1+nsps8-1
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if(i.lt.0 .or. i.gt.npts8-1) cycle
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phi=phi + dphi
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zsum=zsum + c0(i) * cmplx(cos(phi),-sin(phi))
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enddo
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sum=sum + real(zsum)**2 + aimag(zsum)**2
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enddo
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if(sum.gt.smax) then
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idfpk=idf
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smax=sum
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endif
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enddo
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return
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end subroutine peakdf9
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