WSJT-X/lib/ft8/ft8b.f90

472 lines
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Fortran
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subroutine ft8b(dd0,newdat,nQSOProgress,nfqso,nftx,ndepth,lapon,lapcqonly, &
napwid,lsubtract,nagain,ncontest,iaptype,mycall12,hiscall12, &
sync0,f1,xdt,xbase,apsym,nharderrors,dmin,nbadcrc,ipass,iera,msg37,xsnr)
use crc
use timer_module, only: timer
use packjt77
include 'ft8_params.f90'
parameter(NP2=2812)
character*37 msg37,msgsent37
character*12 mycall12,hiscall12,hiscall12_0
character*77 c77
character*6 mycall6,hiscall6,c1,c2
character*13 c13
character*87 cbits
real a(5)
real s8(0:7,NN)
real s2(0:511),s2l(0:511)
real bmeta(174),bmetb(174),bmetc(174)
real llra(174),llrb(174),llrc(174),llrd(174) !Soft symbols
real dd0(15*12000)
integer*1 message77(77),apmask(174),cw(174)
integer apsym(58)
integer mcq(29),mcqru(29),mcqfd(29),mcqtest(29)
integer mrrr(19),m73(19),mrr73(19)
integer itone(NN)
integer icos7(0:6),ip(1)
integer nappasses(0:5) !Number of decoding passes to use for each QSO state
integer naptypes(0:5,4) ! (nQSOProgress, decoding pass) maximum of 4 passes for now
integer ncontest,ncontest0
integer*1, target:: i1hiscall(12)
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logical one(0:511,0:8)
integer graymap(0:7)
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complex cd0(0:3199)
complex ctwk(32)
complex csymb(32)
complex cs(0:7,NN)
logical first,newdat,lsubtract,lapon,lapcqonly,nagain,unpk77_success
data icos7/3,1,4,0,6,5,2/ ! Flipped w.r.t. original FT8 sync array
data mcq/0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0/
data mcqru/0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,1,1,1,1,0,0,1,1,0,0/
data mcqfd/0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,1,0,0,1,0,0,0,1,0/
data mcqtest/0,0,0,0,0,0,0,0,0,1,1,0,0,0,0,1,0,1,0,1,1,1,1,1,1,0,0,1,0/
data mrrr/0,1,1,1,1,1,1,0,1,0,0,1,0,0,1,0,0,0,1/
data m73/0,1,1,1,1,1,1,0,1,0,0,1,0,1,0,0,0,0,1/
data mrr73/0,1,1,1,1,1,1,0,0,1,1,1,0,1,0,1,0,0,1/
data first/.true./
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data graymap/0,1,3,2,5,6,4,7/
save nappasses,naptypes,ncontest0,one,hiscall12_0
if(first.or.(ncontest.ne.ncontest0)) then
mcq=2*mcq-1
mcqfd=2*mcqfd-1
mcqru=2*mcqru-1
mcqtest=2*mcqtest-1
mrrr=2*mrrr-1
m73=2*m73-1
mrr73=2*mrr73-1
nappasses(0)=2
nappasses(1)=2
nappasses(2)=2
nappasses(3)=4
nappasses(4)=4
nappasses(5)=3
! iaptype
!------------------------
! 1 CQ ??? ??? (29+3=32 ap bits)
! 2 MyCall ??? ??? (29+3=32 ap bits)
! 3 MyCall DxCall ??? (58+3=61 ap bits)
! 4 MyCall DxCall RRR (77 ap bits)
! 5 MyCall DxCall 73 (77 ap bits)
! 6 MyCall DxCall RR73 (77 ap bits)
naptypes(0,1:4)=(/1,2,0,0/) ! Tx6 selected (CQ)
naptypes(1,1:4)=(/2,3,0,0/) ! Tx1
naptypes(2,1:4)=(/2,3,0,0/) ! Tx2
naptypes(3,1:4)=(/3,4,5,6/) ! Tx3
naptypes(4,1:4)=(/3,4,5,6/) ! Tx4
naptypes(5,1:4)=(/3,1,2,0/) ! Tx5
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one=.false.
do i=0,511
do j=0,8
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if(iand(i,2**j).ne.0) one(i,j)=.true.
enddo
enddo
first=.false.
ncontest0=ncontest
endif
if(hiscall12.ne.hiscall12_0) then
c13=hiscall12//' '
call save_hash_call(c13,n10,n12,n22)
hiscall12_0=hiscall12
endif
max_iterations=30
nharderrors=-1
nbadcrc=1 ! this is used upstream to flag good decodes.
fs2=12000.0/NDOWN
dt2=1.0/fs2
twopi=8.0*atan(1.0)
delfbest=0.
ibest=0
call timer('ft8_down',0)
call ft8_downsample(dd0,newdat,f1,cd0) !Mix f1 to baseband and downsample
call timer('ft8_down',1)
i0=nint((xdt+0.5)*fs2) !Initial guess for start of signal
smax=0.0
do idt=i0-8,i0+8 !Search over +/- one quarter symbol
call sync8d(cd0,idt,ctwk,0,sync)
if(sync.gt.smax) then
smax=sync
ibest=idt
endif
enddo
xdt2=ibest*dt2 !Improved estimate for DT
! Now peak up in frequency
i0=nint(xdt2*fs2)
smax=0.0
do ifr=-5,5 !Search over +/- 2.5 Hz
delf=ifr*0.5
dphi=twopi*delf*dt2
phi=0.0
do i=1,32
ctwk(i)=cmplx(cos(phi),sin(phi))
phi=mod(phi+dphi,twopi)
enddo
call sync8d(cd0,i0,ctwk,1,sync)
if( sync .gt. smax ) then
smax=sync
delfbest=delf
endif
enddo
a=0.0
a(1)=-delfbest
call twkfreq1(cd0,NP2,fs2,a,cd0)
xdt=xdt2
f1=f1+delfbest !Improved estimate of DF
call sync8d(cd0,i0,ctwk,0,sync)
do k=1,NN
i1=ibest+(k-1)*32
csymb=cmplx(0.0,0.0)
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if( i1.ge.0 .and. i1+31 .le. NP2-1 ) csymb=cd0(i1:i1+31)
call four2a(csymb,32,1,-1,1)
cs(0:7,k)=csymb(1:8)/1e3
s8(0:7,k)=abs(csymb(1:8))
enddo
! sync quality check
is1=0
is2=0
is3=0
do k=1,7
ip=maxloc(s8(:,k))
if(icos7(k-1).eq.(ip(1)-1)) is1=is1+1
ip=maxloc(s8(:,k+36))
if(icos7(k-1).eq.(ip(1)-1)) is2=is2+1
ip=maxloc(s8(:,k+72))
if(icos7(k-1).eq.(ip(1)-1)) is3=is3+1
enddo
! hard sync sum - max is 21
nsync=is1+is2+is3
if(nsync .le. 6) then ! bail out
nbadcrc=1
return
endif
do nsym=1,3
nt=2**(3*nsym)
do ihalf=1,2
do k=1,29,nsym
if(ihalf.eq.1) ks=k+7
if(ihalf.eq.2) ks=k+43
amax=-1.0
do i=0,nt-1
i1=i/64
i2=iand(i,63)/8
i3=iand(i,7)
if(nsym.eq.1) then
s2(i)=abs(cs(graymap(i3),ks))
elseif(nsym.eq.2) then
s2(i)=abs(cs(graymap(i2),ks)+cs(graymap(i3),ks+1))
elseif(nsym.eq.3) then
s2(i)=abs(cs(graymap(i1),ks)+cs(graymap(i2),ks+1)+cs(graymap(i3),ks+2))
else
print*,"Error - nsym must be 1, 2, or 3."
endif
enddo
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s2l(0:nt-1)=log(s2(0:nt-1)+1e-32)
i32=1+(k-1)*3+(ihalf-1)*87
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if(nsym.eq.1) ibmax=2
if(nsym.eq.2) ibmax=5
if(nsym.eq.3) ibmax=8
do ib=0,ibmax
bm=maxval(s2(0:nt-1),one(0:nt-1,ibmax-ib)) - &
maxval(s2(0:nt-1),.not.one(0:nt-1,ibmax-ib))
if(i32+ib .gt.174) cycle
if(nsym.eq.1) then
bmeta(i32+ib)=bm
elseif(nsym.eq.2) then
bmetb(i32+ib)=bm
elseif(nsym.eq.3) then
bmetc(i32+ib)=bm
endif
enddo
enddo
enddo
enddo
call normalizebmet(bmeta,174)
call normalizebmet(bmetb,174)
call normalizebmet(bmetc,174)
scalefac=2.83
llra=scalefac*bmeta
llrb=scalefac*bmetb
llrc=scalefac*bmetc
apmag=maxval(abs(llra))*1.01
! pass #
!------------------------------
! 1 regular decoding, nsym=1
! 2 regular decoding, nsym=2
! 3 regular decoding, nsym=3
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! 4 ap pass 1, nsym=1 (for now?)
! 5 ap pass 2
! 6 ap pass 3
! 7 ap pass 4
if(lapon.or.ncontest.eq.6) then !Hounds always use AP
if(.not.lapcqonly) then
npasses=3+nappasses(nQSOProgress)
else
npasses=4
endif
else
npasses=3
endif
do ipass=1,npasses
llrd=llra
if(ipass.eq.2) llrd=llrb
if(ipass.eq.3) llrd=llrc
if(ipass.le.3) then
apmask=0
iaptype=0
endif
if(ipass .gt. 3) then
llrd=llra
if(.not.lapcqonly) then
iaptype=naptypes(nQSOProgress,ipass-3)
else
iaptype=1
endif
! ncontest=0 : NONE
! 1 : NA_VHF
! 2 : EU_VHF
! 3 : FIELD DAY
! 4 : RTTY
! 5 : FOX
! 6 : HOUND
!
! Conditions that cause us to bail out of AP decoding
if(ncontest.le.4 .and. iaptype.ge.3 .and. (abs(f1-nfqso).gt.napwid .and. abs(f1-nftx).gt.napwid) ) cycle
if(ncontest.eq.5) cycle ! No AP for Foxes
if(ncontest.eq.6.and.f1.gt.950.0) cycle ! Hounds use AP only for signals below 950 Hz
if(iaptype.ge.2 .and. apsym(1).gt.1) cycle ! No, or nonstandard, mycall
if(iaptype.ge.3 .and. apsym(30).gt.1) cycle ! No, or nonstandard, dxcall
if(iaptype.eq.1) then ! CQ or CQ RU or CQ TEST or CQ FD
apmask=0
apmask(1:29)=1
if(ncontest.eq.0) llrd(1:29)=apmag*mcq(1:29)
if(ncontest.eq.1) llrd(1:29)=apmag*mcqtest(1:29)
if(ncontest.eq.2) llrd(1:29)=apmag*mcqtest(1:29)
if(ncontest.eq.3) llrd(1:29)=apmag*mcqfd(1:29)
if(ncontest.eq.4) llrd(1:29)=apmag*mcqru(1:29)
if(ncontest.eq.6) llrd(1:29)=apmag*mcq(1:29)
apmask(75:77)=1
llrd(75:76)=apmag*(-1)
llrd(77)=apmag*(+1)
endif
if(iaptype.eq.2) then ! MyCall,???,???
apmask=0
if(ncontest.eq.0.or.ncontest.eq.1) then
apmask(1:29)=1
llrd(1:29)=apmag*apsym(1:29)
apmask(75:77)=1
llrd(75:76)=apmag*(-1)
llrd(77)=apmag*(+1)
else if(ncontest.eq.2) then
apmask(1:28)=1
llrd(1:28)=apmag*apsym(1:28)
apmask(72:74)=1
llrd(72)=apmag*(-1)
llrd(73)=apmag*(+1)
llrd(74)=apmag*(-1)
apmask(75:77)=1
llrd(75:77)=apmag*(-1)
else if(ncontest.eq.3) then
apmask(1:28)=1
llrd(1:28)=apmag*apsym(1:28)
apmask(75:77)=1
llrd(75:77)=apmag*(-1)
else if(ncontest.eq.4) then
apmask(2:29)=1
llrd(2:29)=apmag*apsym(1:28)
apmask(75:77)=1
llrd(75)=apmag*(-1)
llrd(76:77)=apmag*(+1)
else if(ncontest.eq.6) then ! ??? RR73; MyCall <???> ???
apmask(29:56)=1
llrd(29:56)=apmag*apsym(1:28)
apmask(72:77)=1
llrd(72:73)=apmag*(-1)
llrd(74)=apmag*(+1)
llrd(75:77)=apmag*(-1)
endif
endif
if(iaptype.eq.3) then ! MyCall,DxCall,???
apmask=0
if(ncontest.eq.0.or.ncontest.eq.1.or.ncontest.eq.2.or.ncontest.eq.6) then
apmask(1:58)=1
llrd(1:58)=apmag*apsym
apmask(75:77)=1
llrd(75:76)=apmag*(-1)
llrd(77)=apmag*(+1)
else if(ncontest.eq.3) then ! Field Day
apmask(1:56)=1
llrd(1:28)=apmag*apsym(1:28)
llrd(29:56)=apmag*apsym(30:57)
apmask(72:74)=1
apmask(75:77)=1
llrd(75:77)=apmag*(-1)
else if(ncontest.eq.4) then ! RTTY RU
apmask(2:57)=1
llrd(2:29)=apmag*apsym(1:28)
llrd(30:57)=apmag*apsym(30:57)
apmask(75:77)=1
llrd(75)=apmag*(-1)
llrd(76:77)=apmag*(+1)
endif
endif
if(iaptype.eq.5.and.ncontest.eq.6) cycle !Hound
if(iaptype.eq.4 .or. iaptype.eq.5 .or. iaptype.eq.6) then
apmask=0
if(ncontest.le.4 .or. (ncontest.eq.6.and.iaptype.eq.6)) then
apmask(1:77)=1 ! mycall, hiscall, RRR|73|RR73
llrd(1:58)=apmag*apsym
if(iaptype.eq.4) llrd(59:77)=apmag*mrrr
if(iaptype.eq.5) llrd(59:77)=apmag*m73
if(iaptype.eq.6) llrd(59:77)=apmag*mrr73
else if(ncontest.eq.6.and.iaptype.eq.4) then ! Hound listens for MyCall RR73;...
apmask(1:28)=1
llrd(1:28)=apmag*apsym(1:28)
apmask(72:77)=1
llrd(72:73)=apmag*(-1)
llrd(74)=apmag*(1)
llrd(75:77)=apmag*(-1)
endif
endif
endif
cw=0
call timer('bpd174_91 ',0)
call bpdecode174_91(llrd,apmask,max_iterations,message77,cw,nharderrors, &
niterations)
call timer('bpd174_91 ',1)
dmin=0.0
if(ndepth.eq.3 .and. nharderrors.lt.0) then
ndeep=3
if(abs(nfqso-f1).le.napwid .or. abs(nftx-f1).le.napwid) then
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ndeep=4
endif
if(nagain) ndeep=5
call timer('osd174_91 ',0)
call osd174_91(llrd,apmask,ndeep,message77,cw,nharderrors,dmin)
call timer('osd174_91 ',1)
endif
msg37=' '
if(nharderrors.lt.0 .or. nharderrors.gt.36) cycle
if(count(cw.eq.0).eq.174) cycle !Reject the all-zero codeword
write(c77,'(77i1)') message77
read(c77(72:74),'(b3)') n3
read(c77(75:77),'(b3)') i3
if(i3.gt.4 .or. (i3.eq.0.and.n3.gt.5)) then
cycle
endif
call unpack77(c77,msg37,unpk77_success)
if(.not.unpk77_success) then
cycle
endif
nbadcrc=0 ! If we get this far: valid codeword, valid (i3,n3), nonquirky message.
call get_tones_from_77bits(message77,itone)
if(lsubtract) call subtractft8(dd0,itone,f1,xdt)
xsig=0.0
xnoi=0.0
do i=1,79
xsig=xsig+s8(itone(i),i)**2
ios=mod(itone(i)+4,7)
xnoi=xnoi+s8(ios,i)**2
enddo
xsnr=0.001
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xsnr2=0.001
arg=xsig/xnoi-1.0
if(arg.gt.0.1) xsnr=arg
arg=xsig/xbase/2.6e6-1.0
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if(arg.gt.0.1) xsnr2=arg
xsnr=10.0*log10(xsnr)-27.0
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xsnr2=10.0*log10(xsnr2)-27.0
if(.not.nagain) then
xsnr=xsnr2
endif
if(xsnr .lt. -24.0) xsnr=-24.0
return
enddo
return
end subroutine ft8b
subroutine normalizebmet(bmet,n)
real bmet(n)
bmetav=sum(bmet)/real(n)
bmet2av=sum(bmet*bmet)/real(n)
var=bmet2av-bmetav*bmetav
if( var .gt. 0.0 ) then
bmetsig=sqrt(var)
else
bmetsig=sqrt(bmet2av)
endif
bmet=bmet/bmetsig
return
end subroutine normalizebmet
function bessi0(x)
! From Numerical Recipes
real bessi0,x
double precision p1,p2,p3,p4,p5,p6,p7,q1,q2,q3,q4,q5,q6,q7,q8,q9,y
save p1,p2,p3,p4,p5,p6,p7,q1,q2,q3,q4,q5,q6,q7,q8,q9
data p1,p2,p3,p4,p5,p6,p7/1.0d0,3.5156229d0,3.0899424d0,1.2067492d0, &
0.2659732d0,0.360768d-1,0.45813d-2/
data q1,q2,q3,q4,q5,q6,q7,q8,q9/0.39894228d0,0.1328592d-1, &
0.225319d-2,-0.157565d-2,0.916281d-2,-0.2057706d-1, &
0.2635537d-1,-0.1647633d-1,0.392377d-2/
if (abs(x).lt.3.75) then
y=(x/3.75)**2
bessi0=p1+y*(p2+y*(p3+y*(p4+y*(p5+y*(p6+y*p7)))))
else
ax=abs(x)
y=3.75/ax
bessi0=(exp(ax)/sqrt(ax))*(q1+y*(q2+y*(q3+y*(q4 &
+y*(q5+y*(q6+y*(q7+y*(q8+y*q9))))))))
endif
return
end function bessi0