2007-01-11 16:49:48 -05:00
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subroutine twkfreq(c4aa,c4bb,n5,a)
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complex c4aa(n5)
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complex c4bb(n5)
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real a(5)
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complex w,wstep
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data twopi/6.283185307/
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C Apply AFC corrections to the c4aa and c4bb data
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w=1.0
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2012-05-22 10:28:39 -04:00
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wstep=1.0
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2007-01-11 16:49:48 -05:00
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x0=0.5*(n5+1)
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s=2.0/n5
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do i=1,n5
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x=s*(i-x0)
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if(mod(i,1000).eq.1) then
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p2=1.5*x*x - 0.5
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! p3=2.5*(x**3) - 1.5*x
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! p4=4.375*(x**4) - 3.75*(x**2) + 0.375
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dphi=(a(1) + x*a(2) + p2*a(3)) * (twopi/1378.125)
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wstep=cmplx(cos(dphi),sin(dphi))
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endif
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w=w*wstep
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c4aa(i)=w*c4aa(i)
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c4bb(i)=w*c4bb(i)
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enddo
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return
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end
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