2021-04-09 08:57:41 -04:00
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subroutine spec64(c0,npts2,mode64,jpk,s3,LL,NN)
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parameter (NSPS=3456) !Samples per symbol at 6000 Hz
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complex c0(0:360000) !Complex spectrum of dd()
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complex cs(0:NSPS-1) !Complex symbol spectrum
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real s3(LL,NN) !Synchronized symbol spectra
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real xbase0(LL),xbase(LL)
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nfft=nsps
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fac=1.0/nfft
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do j=1,NN
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jj=j+7 !Skip first Costas array
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if(j.ge.33) jj=j+14 !Skip middle Costas array
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ja=jpk + (jj-1)*nfft
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jb=ja+nfft-1
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cs(0:nfft-1)=fac*c0(ja:jb)
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call four2a(cs,nfft,1,-1,1)
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do ii=1,LL
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i=ii-65
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if(i.lt.0) i=i+nfft
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s3(ii,j)=real(cs(i))**2 + aimag(cs(i))**2
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enddo
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enddo
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df=6000.0/nfft
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do i=1,LL
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call pctile(s3(i,1:NN),NN,45,xbase0(i)) !Get baseline for passband shape
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enddo
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nh=25
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xbase(1:nh-1)=sum(xbase0(1:nh-1))/(nh-1.0)
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xbase(LL-nh+1:LL)=sum(xbase0(LL-nh+1:LL))/(nh-1.0)
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do i=nh,LL-nh
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xbase(i)=sum(xbase0(i-nh+1:i+nh))/(2*nh+1) !Smoothed passband shape
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enddo
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do i=1,LL
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s3(i,1:NN)=s3(i,1:NN)/(xbase(i)+0.001) !Apply frequency equalization
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enddo
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return
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end subroutine spec64
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