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Improvements to msk32 decoder.

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git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6947 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
This commit is contained in:
Steven Franke 2016-07-25 03:10:23 +00:00
parent 418f8b4ca6
commit 9d1498891a
1 changed files with 64 additions and 106 deletions
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170
lib/detectmsk32.f90
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@ -14,10 +14,7 @@ subroutine detectmsk32(cbig,n,mycall,partnercall,lines,nmessages,nutc,ntol,t00)
complex cb(42) !Complex waveform for sync word
complex cbr(42) !Complex waveform for reversed sync word
complex cfac,cca,ccb
complex cc(NPTS)
complex ccr(NPTS)
complex cc1(NPTS)
complex cc2(NPTS)
complex ccr1(NPTS)
complex ccr2(NPTS)
complex bb(6)
@ -25,19 +22,17 @@ subroutine detectmsk32(cbig,n,mycall,partnercall,lines,nmessages,nutc,ntol,t00)
integer, dimension(1) :: iloc
integer icd(0:4095)
integer ihammd(0:4096-1)
integer nhashes(0:31)
integer indices(MAXSTEPS)
integer ipeaks(10)
integer ig24(0:4096-1)
integer ig(0:23,0:4095)
integer isoftbits(32)
integer likelymessages(0:31)
logical qsocontext
logical ismask(NFFT)
real cbi(42),cbq(42)
real detmet(-2:MAXSTEPS+3)
real detfer(MAXSTEPS)
real rcw(12)
real dd(NPTS)
real ddr(NPTS)
real ferrs(MAXCAND)
real pp(12) !Half-sine pulse shape
@ -55,7 +50,7 @@ subroutine detectmsk32(cbig,n,mycall,partnercall,lines,nmessages,nutc,ntol,t00)
'R-04','R-02','R+00','R+02','R+04','R+06','R+08','R+10','R+12', &
'R+14','R+16','R+18','R+20','R+22','R+24', &
'RRR ','73 '/
save df,first,cb,cbr,fs,pi,twopi,dt,s8,rcw,pp,nmatchedfilter,ig24
save df,first,cb,cbr,fs,nhashes,pi,twopi,dt,s8,rcw,pp,nmatchedfilter,ig24
if(first) then
nmatchedfilter=1
@ -103,22 +98,17 @@ subroutine detectmsk32(cbig,n,mycall,partnercall,lines,nmessages,nutc,ntol,t00)
ig(j,i)=2*ib-1
enddo
enddo
do i=0,31
hashmsg=trim(mycall)//' '//trim(partnercall)//' '//rpt(i)
call fmtmsg(hashmsg,iz)
call hash(hashmsg,22,ihash)
nhashes(i)=iand(ihash,127)
enddo
first=.false.
endif
! Define the 32 likely messages
do irpt=0,31
hashmsg=trim(mycall)//' '//trim(partnercall)//' '//rpt(irpt)
call fmtmsg(hashmsg,iz)
call hash(hashmsg,22,ihash)
ihash=iand(ihash,127)
igl=32*ihash + irpt
likelymessages(irpt)=igl
! write(*,*) irpt,hashmsg,igl,ig24(igl)
enddo
qsocontext=.false.
! Fill the detmet, detferr arrays
nstepsize=48 ! 4ms steps
nstep=(n-NPTS)/nstepsize
@ -174,7 +164,6 @@ subroutine detectmsk32(cbig,n,mycall,partnercall,lines,nmessages,nutc,ntol,t00)
enddo ! end of detection-metric and frequency error estimation loop
call indexx(detmet(1:nstep),nstep,indices) !find median of detection metric vector
! xmed=detmet(indices(nstep/2))
xmed=detmet(indices(nstep/4))
detmet=detmet/xmed ! noise floor of detection metric is 1.0
ndet=0
@ -183,7 +172,7 @@ subroutine detectmsk32(cbig,n,mycall,partnercall,lines,nmessages,nutc,ntol,t00)
!write(77,*) i,detmet(i),detfer(i)
!enddo
do ip=1,MAXCAND ! use something like the "clean" algorithm to find candidates
do ip=1,MAXCAND ! find candidates
iloc=maxloc(detmet(1:nstep))
il=iloc(1)
if( (detmet(il) .lt. 4.2) ) exit
@ -196,8 +185,12 @@ subroutine detectmsk32(cbig,n,mycall,partnercall,lines,nmessages,nutc,ntol,t00)
detmet(max(1,il-3):min(nstep,il+3))=0.0
! detmet(il)=0.0
enddo
! ndet=15
! do ip=1,ndet
! times(ip)=ip+0.012
! snrs(ip)=-3.0
! ferrs(ip)=0.0
! write(*,*) ip,times(ip),snrs(ip),ferrs(ip)
! enddo
@ -222,7 +215,7 @@ subroutine detectmsk32(cbig,n,mycall,partnercall,lines,nmessages,nutc,ntol,t00)
if( nsnr .lt. -4 ) nsnr=-4
if( nsnr .gt. 24 ) nsnr=24
! remove coarse freq error - should now be within a few Hz
! remove coarse freq error
call tweak1(cdat,NPTS,-(1500+ferr),cdat)
! attempt frame synchronization
@ -291,7 +284,7 @@ subroutine detectmsk32(cbig,n,mycall,partnercall,lines,nmessages,nutc,ntol,t00)
! Final estimate of the carrier frequency - returned to the calling program
fest=1500+ferr+ferr2
do idf=0,6 ! frequency jitter
if( idf .eq. 0 ) then
deltaf=0.0
@ -352,7 +345,7 @@ subroutine detectmsk32(cbig,n,mycall,partnercall,lines,nmessages,nutc,ntol,t00)
enddo
nbadsync1=(8-sum( (2*hardbits(1:8)-1)*s8r ) )/2
nbadsync=nbadsync1
if( nbadsync .gt. 3 ) cycle
if( nbadsync .gt. 5 ) cycle
! normalize the softsymbols before submitting to decoder
sav=sum(softbits)/32
@ -361,66 +354,53 @@ subroutine detectmsk32(cbig,n,mycall,partnercall,lines,nmessages,nutc,ntol,t00)
softbits=softbits/ssig
isoftbits=softbits*1e4
call timer('search32',0)
if( qsocontext ) then ! search only 32 likely messages.
icd=1e6
ihammd=99
do i=0,31
ncw=ig24(likelymessages(i))
icd(i)=0.0
ihammd(i)=0
do ii=1,24
ib=iand(1,ishft(ncw,1-ii))
ib=2*ib-1
if( ib*softbits(ii+8) .lt. 0 ) then
icd(i)=cd(i)+abs(softbits(ii+8))
ihammd(i)=ihammd(i)+1
endif
enddo
icd=1e6
ihammd=99
do i=0,4096-1
icd(i)=0.0
ihammd(i)=0
do ii=1,24
ib=ig(ii-1,i)
if( ib*isoftbits(ii+8) .lt. 0 ) then
icd(i)=icd(i)+abs(isoftbits(ii+8))
ihammd(i)=ihammd(i)+1
endif
enddo
else ! exhaustive decoder, look at every codeword.
icd=1e6
ihammd=99
do i=0,4096-1
! ncw=ig24(i)
icd(i)=0.0
ihammd(i)=0
do ii=1,24
! ib=iand(1,ishft(ncw,1-ii))
ib=ig(ii-1,i)
! ib=2*ib-1
if( ib*isoftbits(ii+8) .lt. 0 ) then
icd(i)=icd(i)+abs(isoftbits(ii+8))
ihammd(i)=ihammd(i)+1
endif
enddo
enddo
endif
enddo
call timer('search32',1)
icdm=minval(icd)
iloc=minloc(icd)
imsg=iloc(1)-1
nrxrpt=iand(imsg,31)
nrxhash=(imsg-nrxrpt)/32
ihashflag=0
if( nrxhash .eq. nhashes(nrxrpt) ) then
ihashflag=1
endif
icd(imsg)=1e6
icdm2=minval(icd)
iloc=minloc(icd)
imsg2=iloc(1)-1
cdrat=icdm2/(icdm+1)
cdrat2=icdm/(icdm2+1)
if( (icdm .lt. icdbest) .or. ((icdm .eq. icdbest) .and. (ihammd(imsg) .lt. nhammdbest)) ) then
cdratbest = cdrat
cdrat2best = cdrat2
icdbest = icdm
imsgbest = imsg
imsg2best = imsg2
iavbest = iav
ipbest = ip
ipkbest = ipk
idfbest = idf
idbest = id
iphabest = ipha
nbadsyncbest = nbadsync
nhammdbest = ihammd(imsg)
if( ( nhammdbest .eq. 0 ) .and. (icdbest .eq. 0.0) .and. (cdratbest .gt. 2000.0) ) goto 999
cdrat=real(icdm2)/(icdm+1)
if( ihashflag .eq. 1 ) then
if( (icdm .lt. icdbest) .or. ((icdm .eq. icdbest) .and. (ihammd(imsg) .lt. nhammdbest)) ) then
cdratbest = cdrat
icdbest = icdm
imsgbest = imsg
imsg2best = imsg2
iavbest = iav
ipbest = ip
ipkbest = ipk
idfbest = idf
idbest = id
iphabest = ipha
nbadsyncbest = nbadsync
nhammdbest = ihammd(imsg)
if( nhammdbest .eq. 0 ) goto 999
endif
endif
enddo ! phase loop
enddo ! frame averaging loop
enddo ! frequency dithering loop
@ -430,44 +410,22 @@ subroutine detectmsk32(cbig,n,mycall,partnercall,lines,nmessages,nutc,ntol,t00)
999 continue
msgreceived=' '
if( imsgbest .gt. 0 ) then
if( ( nhammdbest+nbadsyncbest .le. 4 ) .and. cdratbest .gt. 5.0 ) then
if( qsocontext ) then
nrxrpt=iand(likelymessages(imsgbest),31)
nrxhash=(likelymessages(imsgbest)-nrxrpt)/32
imessage=likelymessages(imsgbest)
else
nrxrpt=iand(imsgbest,31)
nrxhash=(imsgbest-nrxrpt)/32
imessage=imsgbest
endif
! See if this message has a hash that is expected for a message sent to mycall by partnercall
hashmsg=trim(mycall)//' '//trim(partnercall)//' '//rpt(nrxrpt)
call fmtmsg(hashmsg,iz)
call hash(hashmsg,22,ihash)
ihash=iand(ihash,127)
if(nrxhash.eq.ihash .or. t00.gt.0.0) then
if(nrxhash.eq.ihash) then
if( (icdbest .lt. 5000) .and. ( nhammdbest .le. 4 ) .and. &
(nhammdbest+nbadsyncbest .lt. 5) .and. (cdratbest .gt. 3.5) ) then
nrxrpt=iand(imsgbest,31)
nrxhash=(imsgbest-nrxrpt)/32
nmessages=1
write(msgreceived,'(a1,a,1x,a,a1,1x,a4)') "<",trim(mycall), &
trim(partnercall),">",rpt(nrxrpt)
write(lines(nmessages),1020) nutc,nsnr,t0,nint(fest),msgreceived
1020 format(i6.6,i4,f5.1,i5,' & ',a22)
endif
if(nrxhash.ne.ihash .and. t00.gt.0.0 .and. nsnr.gt.-4) then
nmessages=1
! write(msgreceived,'(a5,1x,a4)') "<...>",rpt(nrxrpt)
write(msgreceived,'(a1,i3,1x,i3,a1,a4)') "<",nrxhash,ihash,">",rpt(nrxrpt)
write(lines(nmessages),1020) nutc,nsnr,t0,nint(fest),msgreceived
endif
! write(*,1022) nutc,ipbest,times(ipbest),snrs(ipbest),fest,nrxrpt,nrxhash, &
! write(*,1022) nutc,ipbest,times(ipbest),snrs(ipbest),fest,nrxrpt,nrxhash,nhashes(nrxrpt), &
! rpt(nrxrpt),imessage,ig24(imessage),nhammdbest, &
! icdbest,cdratbest,cdrat2best,nbadsyncbest,ipkbest,idbest,idfbest,iavbest,iphabest
!1022 format(i6.6,2x,i4,f8.3,f8.2,f8.2,i6,i6,a6,i8,i10,i4,i8,f10.2,f10.2,i5,i5,i5,i5,i5,i5)
endif
! icdbest,cdratbest,nbadsyncbest,ipkbest,idbest,idfbest,iavbest,iphabest
!1022 format(i6.6,2x,i4,f8.3,f8.2,f8.2,i6,i6,i6,a6,i8,i10,i4,i8,f10.2,i5,i5,i5,i5,i5,i5)
endif
endif
return
end subroutine detectmsk32