2012-05-22 13:09:48 -04:00
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subroutine iqcal(nn,c,nfft,gain,phase,zsum,ipk,reject)
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complex c(0:nfft-1)
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complex z,zsum,zave
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if(nn.eq.0) then
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zsum=0.
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endif
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nn=nn+1
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smax=0.
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ipk=1
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do i=1,nfft-1 !Find strongest signal
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s=real(c(i))**2 + aimag(c(i))**2
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if(s.gt.smax) then
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smax=s
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ipk=i
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endif
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enddo
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pimage=real(c(nfft-ipk))**2 + aimag(c(nfft-ipk))**2
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p=smax + pimage
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z=c(ipk)*c(nfft-ipk)/p !Synchronous detection of image
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zsum=zsum+z
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zave=zsum/nn
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tmp=sqrt(1.0 - (2.0*real(zave))**2)
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phase=asin(2.0*aimag(zave)/tmp) !Estimate phase
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gain=tmp/(1.0-2.0*real(zave)) !Estimate gain
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reject=10.0*log10(pimage/smax)
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return
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end subroutine iqcal
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