mirror of https://github.com/saitohirga/WSJT-X.git
76 lines
1.8 KiB
Fortran
76 lines
1.8 KiB
Fortran
subroutine rectify_msk(c,msg,freq2)
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parameter (NSPM=1404)
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complex c(0:NSPM-1) !Received data
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complex cmsg(0:NSPM-1) !Message waveform
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complex c1(0:NSPM-1) !Rectified signal
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complex c2(0:NSPM-1) !Integral of rectified signal
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complex c3(0:2*NSPM-1) !FFT of rectified signal
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complex cfac,z
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character*22 msg,msgsent
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integer i4tone(234)
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ichk=0
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call genmsk(msg,ichk,msgsent,i4tone,itype) !Get tone sequence for msg
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twopi=8.0*atan(1.0)
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dt=1.0/12000.0
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f0=1000.0
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f1=2000.0
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phi=0.
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dphi=0.
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k=-1
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c2=0.
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do j=1,234 !Generate Tx waveform for msg
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if(i4tone(j).eq.0) dphi=twopi*f0*dt
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if(i4tone(j).eq.1) dphi=twopi*f1*dt
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do i=1,6
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k=k+1
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phi=phi+dphi
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cmsg(k)=cmplx(cos(phi),sin(phi))
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c1(k)=conjg(cmsg(k))*c(k)
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if(k.ge.1) c2(k)=c2(k-1) + c1(k)
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enddo
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enddo
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c2(0)=c2(1)
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pha=atan2(aimag(c2(NSPM-1)),real(c2(NSPM-1)))
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cfac=cmplx(cos(pha),-sin(pha))
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c1=cfac*c1
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c2=cfac*c2
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! sq=0.
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! do k=0,NSPM-1
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! pha=atan2(aimag(c2(k)),real(c2(k)))
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! write(61,3001) k,c1(k),c2(k),pha
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!3001 format(i6,7f12.3)
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! sq=sq + aimag(c1(k))**2
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! enddo
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! z=c2(5)
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! do j=1,234
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! k=j*6 - 1
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! if(j.ge.2) z=c2(k)-c2(k-6)
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! pha=atan2(aimag(z),real(z))
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! write(62,3001) j,z,pha
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! enddo
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nfft=2*NSPM
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c3(0:NSPM-1)=c2
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c3(NSPM:nfft-1)=0.
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df=12000.0/nfft
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call four2a(c3,nfft,1,-1,1)
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smax=0.
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do i=0,nfft-1
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f=i*df
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if(i.gt.nfft/2) f=f-12000.0
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s=1.e-10*(real(c3(i))**2 + aimag(c3(i))**2)
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if(s.gt.smax) then
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smax=s
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freq2=1500.0 + f
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endif
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! write(63,3002) f,s,db(s),c3(i)
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!3002 format(f10.1,f12.3,f10.2,2f12.1)
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enddo
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return
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end subroutine rectify_msk
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