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WSJT-X
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Move demod and bit metric calculation to a subroutine. This will make 

it easier to experiment with alternative schemes for demod.
This commit is contained in:
Steve Franke 2019-06-08 08:34:46 -05:00
parent b3d6f5d22e
commit 3c23a05d1f
3 changed files with 133 additions and 111 deletions
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1
CMakeLists.txt
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@ -573,6 +573,7 @@ set (wsjt_FSRCS
lib/sync64.f90
lib/sync65.f90
lib/ft4/getcandidates4.f90
lib/ft4/get_ft4_bitmetrics.f90
lib/ft8/sync8.f90
lib/ft8/sync8d.f90
lib/ft4/sync4d.f90

114
lib/ft4/get_ft4_bitmetrics.f90 Normal file
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@ -0,0 +1,114 @@
subroutine get_ft4_bitmetrics(cd,smax,bitmetrics,badsync)
include 'ft4_params.f90'
parameter (NSS=NSPS/NDOWN,NDMAX=NMAX/NDOWN)
complex cd(0:NN*NSS-1)
complex cs(0:3,NN)
complex csymb(NSS)
integer icos4a(0:3),icos4b(0:3),icos4c(0:3),icos4d(0:3)
integer graymap(0:3)
integer ip(1)
logical one(0:255,0:7) ! 256 4-symbol sequences, 8 bits
logical first
logical badsync
real bitmetrics(2*NN,3)
real s2(0:255)
real s4(0:3,NN)
data icos4a/0,1,3,2/
data icos4b/1,0,2,3/
data icos4c/2,3,1,0/
data icos4d/3,2,0,1/
data graymap/0,1,3,2/
data first/.true./
save first,one
if(first) then
one=.false.
do i=0,255
do j=0,7
if(iand(i,2**j).ne.0) one(i,j)=.true.
enddo
enddo
first=.false.
endif
do k=1,NN
i1=(k-1)*NSS
csymb=cd(i1:i1+NSS-1)
call four2a(csymb,NSS,1,-1,1)
cs(0:3,k)=csymb(1:4)
s4(0:3,k)=abs(csymb(1:4))
enddo
! Sync quality check
is1=0
is2=0
is3=0
is4=0
badsync=.false.
do k=1,4
ip=maxloc(s4(:,k))
if(icos4a(k-1).eq.(ip(1)-1)) is1=is1+1
ip=maxloc(s4(:,k+33))
if(icos4b(k-1).eq.(ip(1)-1)) is2=is2+1
ip=maxloc(s4(:,k+66))
if(icos4c(k-1).eq.(ip(1)-1)) is3=is3+1
ip=maxloc(s4(:,k+99))
if(icos4d(k-1).eq.(ip(1)-1)) is4=is4+1
enddo
nsync=is1+is2+is3+is4 !Number of correct hard sync symbols, 0-16
if(smax .lt. 0.7 .or. nsync .lt. 8) then
badsync=.true.
return
endif
do nseq=1,3 !Try coherent sequences of 1, 2, and 4 symbols
if(nseq.eq.1) nsym=1
if(nseq.eq.2) nsym=2
if(nseq.eq.3) nsym=4
nt=2**(2*nsym)
do ks=1,NN-nsym+1,nsym !87+16=103 symbols.
amax=-1.0
do i=0,nt-1
i1=i/64
i2=iand(i,63)/16
i3=iand(i,15)/4
i4=iand(i,3)
if(nsym.eq.1) then
s2(i)=abs(cs(graymap(i4),ks))
elseif(nsym.eq.2) then
s2(i)=abs(cs(graymap(i3),ks)+cs(graymap(i4),ks+1))
elseif(nsym.eq.4) then
s2(i)=abs(cs(graymap(i1),ks ) + &
cs(graymap(i2),ks+1) + &
cs(graymap(i3),ks+2) + &
cs(graymap(i4),ks+3) &
)
else
print*,"Error - nsym must be 1, 2, or 4."
endif
enddo
ipt=1+(ks-1)*2
if(nsym.eq.1) ibmax=1
if(nsym.eq.2) ibmax=3
if(nsym.eq.4) ibmax=7
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(ipt+ib.gt.2*NN) cycle
bitmetrics(ipt+ib,nseq)=bm
enddo
enddo
enddo
bitmetrics(205:206,2)=bitmetrics(205:206,1)
bitmetrics(201:204,3)=bitmetrics(201:204,2)
bitmetrics(205:206,3)=bitmetrics(205:206,1)
call normalizebmet(bitmetrics(:,1),2*NN)
call normalizebmet(bitmetrics(:,2),2*NN)
call normalizebmet(bitmetrics(:,3),2*NN)
return
end subroutine get_ft4_bitmetrics

129
lib/ft4_decode.f90
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@ -45,43 +45,31 @@ contains
complex cb(0:NDMAX-1)
complex cd(0:NN*NSS-1) !Complex waveform
complex ctwk(2*NSS),ctwk2(2*NSS,-16:16)
complex csymb(NSS)
complex cs(0:3,NN)
real s4(0:3,NN)
real bmeta(2*NN),bmetb(2*NN),bmetc(2*NN)
real a(5)
real bitmetrics(2*NN,3)
real dd(NMAX)
real llr(2*ND),llra(2*ND),llrb(2*ND),llrc(2*ND),llrd(2*ND)
real s2(0:255)
real candidate(3,100)
real savg(NH1),sbase(NH1)
integer apbits(2*ND)
integer apmy_ru(28),aphis_fd(28)
integer icos4a(0:3),icos4b(0:3),icos4c(0:3),icos4d(0:3)
integer*2 iwave(NMAX) !Raw received data
integer*1 message77(77),rvec(77),apmask(2*ND),cw(2*ND)
integer*1 hbits(2*NN)
integer graymap(0:3)
integer i4tone(103)
integer ip(1)
integer nappasses(0:5) ! # of decoding passes for QSO States 0-5
integer naptypes(0:5,4) ! nQSOProgress, decoding pass
integer mcq(29)
integer mrrr(19),m73(19),mrr73(19)
logical nohiscall,unpk77_success
logical one(0:255,0:7) ! 256 4-symbol sequences, 8 bits
logical first, dobigfft
logical dosubtract,doosd
logical badsync
logical, intent(in) :: lapcqonly
data icos4a/0,1,3,2/
data icos4b/1,0,2,3/
data icos4c/2,3,1,0/
data icos4d/3,2,0,1/
data graymap/0,1,3,2/
data first/.true./
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 mrrr/0,1,1,1,1,1,1,0,1,0,0,1,0,0,1,0,0,0,1/
@ -90,7 +78,7 @@ contains
data rvec/0,1,0,0,1,0,1,0,0,1,0,1,1,1,1,0,1,0,0,0,1,0,0,1,1,0,1,1,0, &
1,0,0,1,0,1,1,0,0,0,0,1,0,0,0,1,0,1,0,0,1,1,1,1,0,0,1,0,1, &
0,1,0,1,0,1,1,0,1,1,1,1,1,0,0,0,1,0,1/
save fs,dt,tt,txt,twopi,h,one,first,apbits,nappasses,naptypes, &
save fs,dt,tt,txt,twopi,h,first,apbits,nappasses,naptypes, &
mycall0,hiscall0,cqstr0,ctwk2
this%callback => callback
@ -105,12 +93,6 @@ contains
txt=NZ*dt !Transmission length (s) without ramp up/down
twopi=8.0*atan(1.0)
h=1.0
one=.false.
do i=0,255
do j=0,7
if(iand(i,2**j).ne.0) one(i,j)=.true.
enddo
enddo
do idf=-16,16
a=0.
@ -237,7 +219,7 @@ contains
nd2=ndecodes-nd1
if(nd2.eq.0) exit
endif
candidate=0.0
ncand=0
call timer('getcand4',0)
@ -302,89 +284,14 @@ contains
else
cd(-ibest:ibest+NN*NSS-1)=cb(0:NN*NSS+2*ibest-1)
endif
call timer('four2a ',0)
do k=1,NN
i1=(k-1)*NSS
csymb=cd(i1:i1+NSS-1)
call four2a(csymb,NSS,1,-1,1)
cs(0:3,k)=csymb(1:4)
s4(0:3,k)=abs(csymb(1:4))
enddo
call timer('four2a ',1)
! Sync quality check
is1=0
is2=0
is3=0
is4=0
do k=1,4
ip=maxloc(s4(:,k))
if(icos4a(k-1).eq.(ip(1)-1)) is1=is1+1
ip=maxloc(s4(:,k+33))
if(icos4b(k-1).eq.(ip(1)-1)) is2=is2+1
ip=maxloc(s4(:,k+66))
if(icos4c(k-1).eq.(ip(1)-1)) is3=is3+1
ip=maxloc(s4(:,k+99))
if(icos4d(k-1).eq.(ip(1)-1)) is4=is4+1
enddo
nsync=is1+is2+is3+is4 !Number of correct hard sync symbols, 0-16
if(smax .lt. 0.7 .or. nsync .lt. 8) cycle
do nseq=1,3 !Try coherent sequences of 1, 2, and 4 symbols
if(nseq.eq.1) nsym=1
if(nseq.eq.2) nsym=2
if(nseq.eq.3) nsym=4
nt=2**(2*nsym)
do ks=1,NN-nsym+1,nsym !87+16=103 symbols.
amax=-1.0
do i=0,nt-1
i1=i/64
i2=iand(i,63)/16
i3=iand(i,15)/4
i4=iand(i,3)
if(nsym.eq.1) then
s2(i)=abs(cs(graymap(i4),ks))
elseif(nsym.eq.2) then
s2(i)=abs(cs(graymap(i3),ks)+cs(graymap(i4),ks+1))
elseif(nsym.eq.4) then
s2(i)=abs(cs(graymap(i1),ks ) + &
cs(graymap(i2),ks+1) + &
cs(graymap(i3),ks+2) + &
cs(graymap(i4),ks+3) &
)
else
print*,"Error - nsym must be 1, 2, or 4."
endif
enddo
ipt=1+(ks-1)*2
if(nsym.eq.1) ibmax=1
if(nsym.eq.2) ibmax=3
if(nsym.eq.4) ibmax=7
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(ipt+ib.gt.2*NN) cycle
if(nsym.eq.1) then
bmeta(ipt+ib)=bm
elseif(nsym.eq.2) then
bmetb(ipt+ib)=bm
elseif(nsym.eq.4) then
bmetc(ipt+ib)=bm
endif
enddo
enddo
enddo
bmetb(205:206)=bmeta(205:206)
bmetc(201:204)=bmetb(201:204)
bmetc(205:206)=bmeta(205:206)
call normalizebmet(bmeta,2*NN)
call normalizebmet(bmetb,2*NN)
call normalizebmet(bmetc,2*NN)
call timer('bitmet ',0)
call get_ft4_bitmetrics(cd,smax,bitmetrics,badsync)
call timer('bitmet ',1)
if(badsync) cycle
hbits=0
where(bmeta.ge.0) hbits=1
where(bitmetrics(:,1).ge.0) hbits=1
ns1=count(hbits( 1: 8).eq.(/0,0,0,1,1,0,1,1/))
ns2=count(hbits( 67: 74).eq.(/0,1,0,0,1,1,1,0/))
ns3=count(hbits(133:140).eq.(/1,1,1,0,0,1,0,0/))
@ -393,17 +300,17 @@ contains
if(nsync_qual.lt. 20) cycle
scalefac=2.83
llra( 1: 58)=bmeta( 9: 66)
llra( 59:116)=bmeta( 75:132)
llra(117:174)=bmeta(141:198)
llra( 1: 58)=bitmetrics( 9: 66, 1)
llra( 59:116)=bitmetrics( 75:132, 1)
llra(117:174)=bitmetrics(141:198, 1)
llra=scalefac*llra
llrb( 1: 58)=bmetb( 9: 66)
llrb( 59:116)=bmetb( 75:132)
llrb(117:174)=bmetb(141:198)
llrb( 1: 58)=bitmetrics( 9: 66, 2)
llrb( 59:116)=bitmetrics( 75:132, 2)
llrb(117:174)=bitmetrics(141:198, 2)
llrb=scalefac*llrb
llrc( 1: 58)=bmetc( 9: 66)
llrc( 59:116)=bmetc( 75:132)
llrc(117:174)=bmetc(141:198)
llrc( 1: 58)=bitmetrics( 9: 66, 3)
llrc( 59:116)=bitmetrics( 75:132, 3)
llrc(117:174)=bitmetrics(141:198, 3)
llrc=scalefac*llrc
apmag=maxval(abs(llra))*1.1