76 lines
2.1 KiB
Fortran
76 lines
2.1 KiB
Fortran
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subroutine analytic(d,npts,nfft,c,pc,beq)
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! Convert real data to analytic signal
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parameter (NFFTMAX=1024*1024)
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real d(npts) ! passband signal
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real h(NFFTMAX/2) ! real BPF magnitude
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real*8 pc(5),pclast(5) ! static phase coeffs
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real*8 ac(5),aclast(5) ! amp coeffs
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real*8 fp
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complex corr(NFFTMAX/2) ! complex frequency-dependent correction
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complex c(NFFTMAX) ! analytic signal
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logical*1 beq ! boolean static equalizer flag
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data nfft0/0/
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data aclast/0.0,0.0,0.0,0.0,0.0/
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data pclast/0.0,0.0,0.0,0.0,0.0/
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! data ac/1.0,0.05532,0.11438,0.12918,0.09274/ ! amp coeffs for TS2000
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data ac/1.0,0.0,0.0,0.0,0.0/
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save corr,nfft0,h,ac,aclast,pclast,pi,t,beta
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df=12000.0/nfft
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nh=nfft/2
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if( nfft.ne.nfft0 ) then
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pi=4.0*atan(1.0)
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t=1.0/2000.0
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beta=0.1
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do i=1,nh+1
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ff=(i-1)*df
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f=ff-1500.0
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h(i)=1.0
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if(abs(f).gt.(1-beta)/(2*t) .and. abs(f).le.(1+beta)/(2*t)) then
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h(i)=h(i)*0.5*(1+cos((pi*t/beta )*(abs(f)-(1-beta)/(2*t))))
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elseif( abs(f) .gt. (1+beta)/(2*t) ) then
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h(i)=0.0
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endif
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enddo
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nfft0=nfft
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endif
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if( any(aclast .ne. ac) .or. any(pclast .ne. pc) ) then
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aclast=ac
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pclast=pc
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! write(*,3001) pc
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!3001 format('Phase coeffs:',5f12.6)
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do i=1,nh+1
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ff=(i-1)*df
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f=ff-1500.0
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fp=f/1000.0
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corr(i)=ac(1)+fp*(ac(2)+fp*(ac(3)+fp*(ac(4)+fp*ac(5))))
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pd=fp*fp*(pc(3)+fp*(pc(4)+fp*pc(5))) ! ignore 1st two terms
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corr(i)=corr(i)*cmplx(cos(pd),sin(pd))
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enddo
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endif
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fac=2.0/nfft
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c(1:npts)=fac*d(1:npts)
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c(npts+1:nfft)=0.
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call four2a(c,nfft,1,-1,1) !Forward c2c FFT
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if( beq ) then
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c(1:nh+1)=h(1:nh+1)*corr(1:nh+1)*c(1:nh+1)
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else
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c(1:nh+1)=h(1:nh+1)*c(1:nh+1)
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endif
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c(1)=0.5*c(1) !Half of DC term
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c(nh+2:nfft)=0. !Zero the negative frequencies
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call four2a(c,nfft,1,1,1) !Inverse c2c FFT
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return
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end subroutine analytic
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