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30 lines
608 B
Fortran
30 lines
608 B
Fortran
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subroutine lpf1(dd,jz,dat,jz2)
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parameter (NFFT1=64*11025,NFFT2=32*11025)
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real dd(jz)
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real dat(jz)
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real x(NFFT1)
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complex cx(0:NFFT1/2)
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equivalence (x,cx)
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save x,cx
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fac=1.0/float(NFFT1)
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x(1:jz)=fac*dd(1:jz)
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x(jz+1:NFFT1)=0.0
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call four2a(x,NFFT1,1,-1,0) !Forwarxd FFT, r2c
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cx(NFFT2/2:)=0.0
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! df=11025.0/NFFT1
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! do i=1,NFFT1/2
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! sx=real(cx(i))**2 + aimag(cx(i))**2
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! write(50,3000) i*df,sx
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!3000 format(f15.6,e12.3)
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! enddo
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call four2a(cx,NFFT2,1,1,-1) !Inverse FFT, c2r
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jz2=jz/2
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dat(1:jz2)=x(1:jz2)
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return
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end subroutine lpf1
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