mirror of https://github.com/pavel-demin/ft8d.git
424 lines
12 KiB
Fortran
424 lines
12 KiB
Fortran
subroutine ft8b(dd0,newdat,nQSOProgress,nfqso,nftx,ndepth,lapon,lapcqonly, &
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napwid,nagain,iaptype,f1,xdt,xbase,apsym,nharderrors,dmin, &
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nbadcrc,ipass,msgcall,msggrid,xsnr)
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use crc
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include 'ft8_params.f90'
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parameter(NP2=2812)
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character msgcall*12,msggrid*4,message*22
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real a(5)
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real s1(0:7,ND),s2(0:7,NN),s1sort(8*ND)
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real ps(0:7),psl(0:7)
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real bmeta(3*ND),bmetb(3*ND),bmetap(3*ND)
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real llr(3*ND),llra(3*ND),llr0(3*ND),llr1(3*ND),llrap(3*ND) !Soft symbols
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complex dd0(NMAX)
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integer*1 decoded(KK),apmask(3*ND),cw(3*ND)
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integer apsym(KK)
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integer mcq(28),mde(28),mrrr(16),m73(16),mrr73(16)
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integer itone(NN)
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integer indxs1(8*ND)
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integer icos7(0:6),ip(1)
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integer nappasses(0:5) !Number of decoding passes to use for each QSO state
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integer naptypes(0:5,4) ! (nQSOProgress, decoding pass) maximum of 4 passes for now
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complex cd0(3200)
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complex ctwk(32)
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complex csymb(32)
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logical first,newdat,lapon,lapcqonly,nagain
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equivalence (s1,s1sort)
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data icos7/2,5,6,0,4,1,3/
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data mcq/1,1,1,1,1,0,1,0,0,0,0,0,1,0,0,0,0,0,1,1,0,0,0,1,1,0,0,1/
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data mrrr/0,1,1,1,1,1,1,0,1,1,0,0,1,1,1,1/
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data m73/0,1,1,1,1,1,1,0,1,1,0,1,0,0,0,0/
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data mde/1,1,1,1,1,1,1,1,0,1,1,0,0,1,0,0,0,0,0,1,1,1,0,1,0,0,0,1/
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data mrr73/0,0,0,0,0,0,1,0,0,0,0,1,0,1,0,1/
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data first/.true./
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save nappasses,naptypes
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if(first) then
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mcq=2*mcq-1
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mde=2*mde-1
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mrrr=2*mrrr-1
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m73=2*m73-1
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mrr73=2*mrr73-1
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nappasses(0)=2
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nappasses(1)=2
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nappasses(2)=2
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nappasses(3)=4
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nappasses(4)=4
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nappasses(5)=3
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! iaptype
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!------------------------
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! 1 CQ ??? ???
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! 2 MyCall ??? ???
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! 3 MyCall DxCall ???
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! 4 MyCall DxCall RRR
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! 5 MyCall DxCall 73
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! 6 MyCall DxCall RR73
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! 7 ??? DxCall ???
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naptypes(0,1:4)=(/1,2,0,0/)
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naptypes(1,1:4)=(/2,3,0,0/)
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naptypes(2,1:4)=(/2,3,0,0/)
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naptypes(3,1:4)=(/3,4,5,6/)
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naptypes(4,1:4)=(/3,4,5,6/)
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naptypes(5,1:4)=(/3,1,2,0/)
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first=.false.
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endif
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max_iterations=30
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nharderrors=-1
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fs2=4000.0/NDOWN
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dt2=1.0/fs2
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twopi=8.0*atan(1.0)
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delfbest=0.
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ibest=0
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call ft8_downsample(dd0,newdat,f1,cd0) !Mix f1 to baseband and downsample
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i0=nint((xdt+0.5)*fs2) !Initial guess for start of signal
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smax=0.0
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do idt=i0-8,i0+8 !Search over +/- one quarter symbol
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call sync8d(cd0,idt,ctwk,0,sync)
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if(sync.gt.smax) then
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smax=sync
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ibest=idt
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endif
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enddo
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xdt2=ibest*dt2 !Improved estimate for DT
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! Now peak up in frequency
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i0=nint(xdt2*fs2)
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smax=0.0
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do ifr=-5,5 !Search over +/- 2.5 Hz
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delf=ifr*0.5
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dphi=twopi*delf*dt2
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phi=0.0
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do i=1,32
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ctwk(i)=cmplx(cos(phi),sin(phi))
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phi=mod(phi+dphi,twopi)
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enddo
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call sync8d(cd0,i0,ctwk,1,sync)
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if( sync .gt. smax ) then
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smax=sync
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delfbest=delf
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endif
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enddo
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a=0.0
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a(1)=-delfbest
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call twkfreq1(cd0,NP2,fs2,a,cd0)
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xdt=xdt2
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f1=f1+delfbest !Improved estimate of DF
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call sync8d(cd0,i0,ctwk,2,sync)
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j=0
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do k=1,NN
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i1=ibest+(k-1)*32
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csymb=cmplx(0.0,0.0)
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if( i1.ge.1 .and. i1+31 .le. NP2 ) csymb=cd0(i1:i1+31)
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call four2a(csymb,32,1,-1,1)
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s2(0:7,k)=abs(csymb(1:8))/1e3
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enddo
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! sync quality check
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is1=0
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is2=0
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is3=0
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do k=1,7
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ip=maxloc(s2(:,k))
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if(icos7(k-1).eq.(ip(1)-1)) is1=is1+1
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ip=maxloc(s2(:,k+36))
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if(icos7(k-1).eq.(ip(1)-1)) is2=is2+1
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ip=maxloc(s2(:,k+72))
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if(icos7(k-1).eq.(ip(1)-1)) is3=is3+1
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enddo
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! hard sync sum - max is 21
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nsync=is1+is2+is3
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if(nsync .le. 6) then ! bail out
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nbadcrc=1
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return
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endif
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j=0
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do k=1,NN
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if(k.le.7) cycle
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if(k.ge.37 .and. k.le.43) cycle
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if(k.gt.72) cycle
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j=j+1
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s1(0:7,j)=s2(0:7,k)
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enddo
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call indexx(s1sort,8*ND,indxs1)
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xmeds1=s1sort(indxs1(nint(0.5*8*ND)))
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s1=s1/xmeds1
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do j=1,ND
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i4=3*j-2
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i2=3*j-1
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i1=3*j
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! Max amplitude
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ps=s1(0:7,j)
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r1=max(ps(1),ps(3),ps(5),ps(7))-max(ps(0),ps(2),ps(4),ps(6))
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r2=max(ps(2),ps(3),ps(6),ps(7))-max(ps(0),ps(1),ps(4),ps(5))
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r4=max(ps(4),ps(5),ps(6),ps(7))-max(ps(0),ps(1),ps(2),ps(3))
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bmeta(i4)=r4
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bmeta(i2)=r2
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bmeta(i1)=r1
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bmetap(i4)=r4
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bmetap(i2)=r2
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bmetap(i1)=r1
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! Max log metric
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psl=log(ps)
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r1=max(psl(1),psl(3),psl(5),psl(7))-max(psl(0),psl(2),psl(4),psl(6))
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r2=max(psl(2),psl(3),psl(6),psl(7))-max(psl(0),psl(1),psl(4),psl(5))
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r4=max(psl(4),psl(5),psl(6),psl(7))-max(psl(0),psl(1),psl(2),psl(3))
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bmetb(i4)=r4
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bmetb(i2)=r2
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bmetb(i1)=r1
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! Metric for Cauchy noise
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! r1=log(ps(1)**3+ps(3)**3+ps(5)**3+ps(7)**3)- &
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! log(ps(0)**3+ps(2)**3+ps(4)**3+ps(6)**3)
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! r2=log(ps(2)**3+ps(3)**3+ps(6)**3+ps(7)**3)- &
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! log(ps(0)**3+ps(1)**3+ps(4)**3+ps(5)**3)
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! r4=log(ps(4)**3+ps(5)**3+ps(6)**3+ps(7)**3)- &
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! log(ps(0)**3+ps(1)**3+ps(2)**3+ps(3)**3)
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! Metric for AWGN, no fading
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! bscale=2.5
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! b0=bessi0(bscale*ps(0))
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! b1=bessi0(bscale*ps(1))
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! b2=bessi0(bscale*ps(2))
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! b3=bessi0(bscale*ps(3))
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! b4=bessi0(bscale*ps(4))
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! b5=bessi0(bscale*ps(5))
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! b6=bessi0(bscale*ps(6))
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! b7=bessi0(bscale*ps(7))
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! r1=log(b1+b3+b5+b7)-log(b0+b2+b4+b6)
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! r2=log(b2+b3+b6+b7)-log(b0+b1+b4+b5)
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! r4=log(b4+b5+b6+b7)-log(b0+b1+b2+b3)
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if(nQSOProgress .eq. 0 .or. nQSOProgress .eq. 5) then
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! When bits 88:115 are set as ap bits, bit 115 lives in symbol 39 along
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! with no-ap bits 116 and 117. Take care of metrics for bits 116 and 117.
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if(j.eq.39) then ! take care of bits that live in symbol 39
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if(apsym(28).lt.0) then
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bmetap(i2)=max(ps(2),ps(3))-max(ps(0),ps(1))
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bmetap(i1)=max(ps(1),ps(3))-max(ps(0),ps(2))
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else
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bmetap(i2)=max(ps(6),ps(7))-max(ps(4),ps(5))
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bmetap(i1)=max(ps(5),ps(7))-max(ps(4),ps(6))
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endif
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endif
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endif
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! When bits 116:143 are set as ap bits, bit 115 lives in symbol 39 along
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! with ap bits 116 and 117. Take care of metric for bit 115.
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! if(j.eq.39) then ! take care of bit 115
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! iii=2*(apsym(29)+1)/2 + (apsym(30)+1)/2 ! known values of bits 116 & 117
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! if(iii.eq.0) bmetap(i4)=ps(4)-ps(0)
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! if(iii.eq.1) bmetap(i4)=ps(5)-ps(1)
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! if(iii.eq.2) bmetap(i4)=ps(6)-ps(2)
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! if(iii.eq.3) bmetap(i4)=ps(7)-ps(3)
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! endif
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! bit 144 lives in symbol 48 and will be 1 if it is set as an ap bit.
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! take care of metrics for bits 142 and 143
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if(j.eq.48) then ! bit 144 is always 1
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bmetap(i4)=max(ps(5),ps(7))-max(ps(1),ps(3))
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bmetap(i2)=max(ps(3),ps(7))-max(ps(1),ps(5))
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endif
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! bit 154 lives in symbol 52 and will be 0 if it is set as an ap bit
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! take care of metrics for bits 155 and 156
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if(j.eq.52) then ! bit 154 will be 0 if it is set as an ap bit.
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bmetap(i2)=max(ps(2),ps(3))-max(ps(0),ps(1))
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bmetap(i1)=max(ps(1),ps(3))-max(ps(0),ps(2))
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endif
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enddo
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call normalizebmet(bmeta,3*ND)
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call normalizebmet(bmetb,3*ND)
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call normalizebmet(bmetap,3*ND)
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scalefac=2.83
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llr0=scalefac*bmeta
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llr1=scalefac*bmetb
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llra=scalefac*bmetap ! llr's for use with ap
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apmag=scalefac*(maxval(abs(bmetap))*1.01)
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! pass #
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!------------------------------
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! 1 regular decoding
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! 2 erase 24
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! 3 erase 48
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! 4 ap pass 1
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! 5 ap pass 2
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! 6 ap pass 3
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! 7 ap pass 4, etc.
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if(lapon) then
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if(.not.lapcqonly) then
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npasses=4+nappasses(nQSOProgress)
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else
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npasses=5
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endif
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else
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npasses=4
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endif
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do ipass=1,npasses
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llr=llr0
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if(ipass.eq.2) llr=llr1
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if(ipass.eq.3) llr(1:24)=0.
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if(ipass.eq.4) llr(1:48)=0.
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if(ipass.le.4) then
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apmask=0
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llrap=llr
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iaptype=0
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endif
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if(ipass .gt. 4) then
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if(.not.lapcqonly) then
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iaptype=naptypes(nQSOProgress,ipass-4)
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else
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iaptype=1
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endif
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if(iaptype.ge.3 .and. (abs(f1-nfqso).gt.napwid .and. abs(f1-nftx).gt.napwid) ) cycle
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if(iaptype.eq.1 .or. iaptype.eq.2 ) then ! AP,???,???
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apmask=0
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apmask(88:115)=1 ! first 28 bits are AP
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apmask(144)=1 ! not free text
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llrap=llr
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if(iaptype.eq.1) llrap(88:115)=apmag*mcq
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if(iaptype.eq.2) llrap(88:115)=apmag*apsym(1:28)
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llrap(116:117)=llra(116:117)
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llrap(142:143)=llra(142:143)
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llrap(144)=-apmag
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endif
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if(iaptype.eq.3) then ! mycall, dxcall, ???
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apmask=0
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apmask(88:115)=1 ! mycall
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apmask(116:143)=1 ! hiscall
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apmask(144)=1 ! not free text
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llrap=llr
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llrap(88:143)=apmag*apsym(1:56)
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llrap(144)=-apmag
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endif
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if(iaptype.eq.4 .or. iaptype.eq.5 .or. iaptype.eq.6) then
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apmask=0
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apmask(88:115)=1 ! mycall
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apmask(116:143)=1 ! hiscall
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apmask(144:159)=1 ! RRR or 73 or RR73
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llrap=llr
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llrap(88:143)=apmag*apsym(1:56)
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if(iaptype.eq.4) llrap(144:159)=apmag*mrrr
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if(iaptype.eq.5) llrap(144:159)=apmag*m73
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if(iaptype.eq.6) llrap(144:159)=apmag*mrr73
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endif
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if(iaptype.eq.7) then ! ???, dxcall, ???
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apmask=0
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apmask(116:143)=1 ! hiscall
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apmask(144)=1 ! not free text
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llrap=llr
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llrap(115)=llra(115)
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llrap(116:143)=apmag*apsym(29:56)
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llrap(144)=-apmag
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endif
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endif
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cw=0
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call bpdecode174(llrap,apmask,max_iterations,decoded,cw,nharderrors, &
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niterations)
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dmin=0.0
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if(ndepth.eq.3 .and. nharderrors.lt.0) then
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ndeep=3
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if(abs(nfqso-f1).le.napwid .or. abs(nftx-f1).le.napwid) then
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if((ipass.eq.3 .or. ipass.eq.4) .and. .not.nagain) then
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ndeep=3
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else
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ndeep=4
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endif
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endif
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if(nagain) ndeep=5
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call osd174(llrap,apmask,ndeep,decoded,cw,nharderrors,dmin)
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endif
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nbadcrc=1
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message=' '
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xsnr=-99.0
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if(count(cw.eq.0).eq.174) cycle !Reject the all-zero codeword
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if(nharderrors.ge.0 .and. nharderrors+dmin.lt.60.0 .and. &
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.not.(sync.lt.2.0 .and. nharderrors.gt.35) .and. &
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.not.(ipass.gt.2 .and. nharderrors.gt.39) .and. &
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.not.(ipass.eq.4 .and. nharderrors.gt.30) &
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) then
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call chkcrc12a(decoded,nbadcrc)
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else
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nharderrors=-1
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cycle
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endif
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if(nbadcrc.eq.0) then
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call extractmessage174(decoded,message,msgcall,msggrid,ncrcflag)
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call genft8(message,0,itone)
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xsig=0.0
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xnoi=0.0
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do i=1,79
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xsig=xsig+s2(itone(i),i)**2
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ios=mod(itone(i)+4,7)
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xnoi=xnoi+s2(ios,i)**2
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enddo
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xsnr=0.001
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if(xnoi.gt.0 .and. xnoi.lt.xsig) xsnr=xsig/xnoi-1.0
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xsnr=10.0*log10(xsnr)-27.0
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xsnr2=db(xsig/xbase - 1.0) - 32.0
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if(.not.nagain) xsnr=xsnr2
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if(xsnr .lt. -24.0) xsnr=-24.0
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return
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endif
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enddo
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return
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end subroutine ft8b
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subroutine normalizebmet(bmet,n)
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real bmet(n)
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bmetav=sum(bmet)/real(n)
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bmet2av=sum(bmet*bmet)/real(n)
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var=bmet2av-bmetav*bmetav
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if( var .gt. 0.0 ) then
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bmetsig=sqrt(var)
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else
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bmetsig=sqrt(bmet2av)
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endif
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bmet=bmet/bmetsig
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return
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end subroutine normalizebmet
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function bessi0(x)
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! From Numerical Recipes
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real bessi0,x
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double precision p1,p2,p3,p4,p5,p6,p7,q1,q2,q3,q4,q5,q6,q7,q8,q9,y
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save p1,p2,p3,p4,p5,p6,p7,q1,q2,q3,q4,q5,q6,q7,q8,q9
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data p1,p2,p3,p4,p5,p6,p7/1.0d0,3.5156229d0,3.0899424d0,1.2067492d0, &
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0.2659732d0,0.360768d-1,0.45813d-2/
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data q1,q2,q3,q4,q5,q6,q7,q8,q9/0.39894228d0,0.1328592d-1, &
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0.225319d-2,-0.157565d-2,0.916281d-2,-0.2057706d-1, &
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0.2635537d-1,-0.1647633d-1,0.392377d-2/
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if (abs(x).lt.3.75) then
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y=(x/3.75)**2
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bessi0=p1+y*(p2+y*(p3+y*(p4+y*(p5+y*(p6+y*p7)))))
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else
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ax=abs(x)
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y=3.75/ax
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bessi0=(exp(ax)/sqrt(ax))*(q1+y*(q2+y*(q3+y*(q4 &
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+y*(q5+y*(q6+y*(q7+y*(q8+y*q9))))))))
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endif
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return
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end function bessi0
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