mirror of https://github.com/saitohirga/WSJT-X.git
108 lines
2.3 KiB
Fortran
108 lines
2.3 KiB
Fortran
subroutine msk144sync(cdat,nframes,ntol,ndf,navmask,npeaks,fc,fest,npklocs,nsuccess,c)
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parameter (NSPM=864)
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complex cdat(NSPM*nframes)
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complex cdat2(NSPM*nframes)
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complex c(NSPM) !Coherently averaged complex data
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complex ct2(2*NSPM)
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complex cs(NSPM)
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complex cb(42) !Complex waveform for sync word
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complex cc(0:NSPM-1)
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integer s8(8)
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integer iloc(1)
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integer npklocs(npeaks)
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integer navmask(nframes) ! defines which frames to average
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real cbi(42),cbq(42)
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real pkamps(npeaks)
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real xcc(0:NSPM-1)
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real xccs(0:NSPM-1)
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real pp(12) !Half-sine pulse shape
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logical first
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data first/.true./
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data s8/0,1,1,1,0,0,1,0/
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save first,cb,fs,pi,twopi,dt,s8,pp
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! call system_clock(count0,clkfreq)
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if(first) then
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pi=4.0*atan(1.0)
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twopi=8.0*atan(1.0)
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fs=12000.0
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dt=1.0/fs
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do i=1,12 !Define half-sine pulse
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angle=(i-1)*pi/12.0
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pp(i)=sin(angle)
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enddo
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! Define the sync word waveforms
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s8=2*s8-1
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cbq(1:6)=pp(7:12)*s8(1)
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cbq(7:18)=pp*s8(3)
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cbq(19:30)=pp*s8(5)
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cbq(31:42)=pp*s8(7)
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cbi(1:12)=pp*s8(2)
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cbi(13:24)=pp*s8(4)
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cbi(25:36)=pp*s8(6)
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cbi(37:42)=pp(1:6)*s8(8)
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cb=cmplx(cbi,cbq)
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first=.false.
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endif
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navg=sum(navmask)
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xmax=0.0
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bestf=0.0
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n=nframes*NSPM
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do ifr=-ntol,ntol,ndf !Find freq that maximizes sync
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ferr=ifr
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call tweak1(cdat,n,-(fc+ferr),cdat2)
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c=0
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do i=1,nframes
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ib=(i-1)*NSPM+1
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ie=ib+NSPM-1
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if( navmask(i) .eq. 1 ) then
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c(1:NSPM)=c(1:NSPM)+cdat2(ib:ie)
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endif
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enddo
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cc=0
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ct2(1:NSPM)=c
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ct2(NSPM+1:2*NSPM)=c
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do ish=0,NSPM-1
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cc(ish)=dot_product(ct2(1+ish:42+ish)+ct2(336+ish:377+ish),cb(1:42))
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enddo
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xcc=abs(cc)
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xb=maxval(xcc)/(48.0*sqrt(float(navg)))
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if(xb.gt.xmax) then
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xmax=xb
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bestf=ferr
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cs=c
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xccs=xcc
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endif
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enddo
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fest=fc+bestf
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c=cs
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xcc=xccs
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! Find npeaks largest peaks
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do ipk=1,npeaks
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iloc=maxloc(xcc)
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ic2=iloc(1)
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npklocs(ipk)=ic2
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pkamps(ipk)=xcc(ic2-1)
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xcc(max(0,ic2-7):min(NSPM-1,ic2+7))=0.0
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enddo
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if( xmax .lt. 0.7 ) then
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nsuccess=0
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else
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nsuccess=1
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endif
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return
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end subroutine msk144sync
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