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git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@7159 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
17 lines
338 B
Fortran
17 lines
338 B
Fortran
subroutine degrade_snr(d2,npts,db,bw)
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integer*2 d2(npts)
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real dat(60*12000)
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dat(1:npts)=d2
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p0=dot_product(dat(1:npts),dat(1:npts))/npts
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if(bw.gt.0.0) p0=p0*6000.0/bw
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s=sqrt(p0*(10.0**(0.1*db) - 1.0))
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fac=sqrt(p0/(p0+s*s))
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do i=1,npts
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d2(i)=nint(fac*(dat(i) + s*gran()))
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enddo
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return
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end subroutine degrade_snr
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