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https://github.com/saitohirga/WSJT-X.git
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95ab66807d
git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6939 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
121 lines
3.1 KiB
Fortran
121 lines
3.1 KiB
Fortran
subroutine sync64(dd,nf1,nf2,maxf1,dtx,f0,kpk,snrdb,s3a)
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parameter (NMAX=60*12000) !Max size of raw data at 12000 Hz
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parameter (NSPS=2304) !Samples per symbol at 4000 Hz
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parameter (NSPC=7*NSPS) !Samples per Costas array
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real dd(NMAX) !Raw data
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real x(672000) !Up to 56 s at 12000 Hz
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real t(5)
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real s3a(0:63,1:63)
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real s0(0:NSPC-1)
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real s1(0:NSPC-1)
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real s2(0:NSPC-1)
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real s3(0:NSPC-1)
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real s0a(0:NSPC-1)
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integer*8 count0,count1,clkfreq
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integer icos7(0:6)
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integer ipk0(1)
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complex cc(0:NSPC-1)
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complex c0(0:336000)
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complex c1(0:NSPC-1)
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complex c2(0:NSPC-1)
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complex c3(0:NSPC-1)
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equivalence (x,c0)
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data icos7/2,5,6,0,4,1,3/ !Costas 7x7 pattern
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save
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twopi=8.0*atan(1.0)
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dfgen=12000.0/6912.0
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k=-1
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phi=0.
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do j=0,6
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dphi=twopi*icos7(j)*dfgen/4000.0
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do i=1,2304
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phi=phi + dphi
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if(phi.gt.twopi) phi=phi-twopi
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k=k+1
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cc(k)=cmplx(cos(phi),sin(phi))
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enddo
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enddo
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npts0=54*12000
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nfft1=672000
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nfft2=nfft1/3
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df1=12000.0/nfft1
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fac=2.0/nfft1
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x=fac*dd(1:nfft1)
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call system_clock(count0,clkfreq)
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call four2a(c0,nfft1,1,-1,0) !Forward r2c FFT
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call four2a(c0,nfft2,1,1,1) !Inverse c2c FFT; c0 is analytic sig
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call system_clock(count1,clkfreq)
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t(1)=float(count1-count0)/float(clkfreq)
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npts2=npts0/3 !Downsampled complex data length
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nfft3=NSPC
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nh3=nfft3/2
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df3=4000.0/nfft3
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ia=nint(nf1/df3)
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ib=nint(nf2/df3)
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iz=ib-ia+1
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snr=0.
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jpk=0
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ja=0
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jb=6*4000
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jstep=200
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ka=-maxf1
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kb=maxf1
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ipk=0
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kpk=0
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call system_clock(count0,clkfreq)
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do iter=1,2
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do j1=ja,jb,jstep
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j2=j1 + 39*2304
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j3=j1 + 77*2304
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c1=1.e-4*c0(j1:j1+NSPC-1) * conjg(cc)
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call four2a(c1,nfft3,1,-1,1)
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c2=1.e-4*c0(j2:j2+NSPC-1) * conjg(cc)
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call four2a(c2,nfft3,1,-1,1)
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c3=1.e-4*c0(j3:j3+NSPC-1) * conjg(cc)
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call four2a(c3,nfft3,1,-1,1)
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s0=0.
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s1=0.
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s2=0.
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s3=0.
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do i=ia,ib
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freq=i*df3
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s1(i)=real(c1(i))**2 + aimag(c1(i))**2
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s2(i)=real(c2(i))**2 + aimag(c2(i))**2
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s3(i)=real(c3(i))**2 + aimag(c3(i))**2
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enddo
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do k=ka,kb
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s0(ia:ib)=s1(ia-k:ib-k) + s2(ia:ib) + s3(ia+k:ib+k)
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call smo121(s0(ia:ib),iz)
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call averms(s0(ia:ib),iz,14,ave,rms)
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s=(maxval(s0(ia:ib))-ave)/rms
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if(s.gt.snr) then
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jpk=j1
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s0a=s0
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snr=s
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dtx=jpk/4000.0 - 1.0
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ipk0=maxloc(s0(ia:ib))
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ipk=ipk0(1)
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f0=(ipk+ia-1)*df3
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kpk=k
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! write(16,3101) jpk,ipk,kpk,dtx,f0,snr
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!3101 format(3i5,f8.3,f8.2,f10.1)
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endif
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enddo
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enddo
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ja=jpk-2*jstep
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jb=jpk+2*jstep
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jstep=10
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! ka=kpk
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! kb=kpk
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enddo
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call system_clock(count1,clkfreq)
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t(2)=float(count1-count0)/float(clkfreq)
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snrdb=10.0*log10(snr)-39.0
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return
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end subroutine sync64
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