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git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@2746 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
51 lines
1012 B
Fortran
51 lines
1012 B
Fortran
subroutine peakdt9(c0,npts8,nsps8,istart,foffset,idtpk)
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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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smax=0.
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tstep=0.0625*nsps8/1500.0
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idtmax=2.5/tstep
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f0=foffset
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dphi=twopi*f0/1500.0
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idtstep=4
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if(idtmax.lt.30) idtstep=2
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if(idtmax.lt.15) idtstep=1
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idt1=-idtmax
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idt2=idtmax
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10 do idt=idt1,idt2,idtstep
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i0=istart + 0.0625*nsps8*idt
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sum=0.
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do j=1,16
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i1=max(0,(ii(j)-1)*nsps8 + i0)
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i2=min(npts8-1,i1+nsps8-1)
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phi=0.
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zsum=0.
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do i=i1,i2
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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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idtpk=idt
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smax=sum
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endif
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enddo
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if(idtstep.gt.1) then
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idtstep=1
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idt1=idtpk-3
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idt2=idtpk+3
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go to 10
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endif
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return
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end subroutine peakdt9
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