From 039c9c023e50853cefe423bb664d74845df53338 Mon Sep 17 00:00:00 2001 From: Steven Franke Date: Sun, 10 Jul 2016 02:19:43 +0000 Subject: [PATCH] Tweaks to msk32 decoder. git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6902 ab8295b8-cf94-4d9e-aec4-7959e3be5d79 --- lib/detectmsk32.f90 | 92 +++++++++++++++++++-------------------------- 1 file changed, 39 insertions(+), 53 deletions(-) diff --git a/lib/detectmsk32.f90 b/lib/detectmsk32.f90 index ae2c9f4c6..a7d2a1452 100644 --- a/lib/detectmsk32.f90 +++ b/lib/detectmsk32.f90 @@ -176,14 +176,14 @@ subroutine detectmsk32(cbig,n,mycall,partnercall,lines,nmessages,nutc,ntol) do ip=1,MAXCAND ! use something like the "clean" algorithm to find candidates iloc=maxloc(detmet(1:nstep)) il=iloc(1) - if( (detmet(il) .lt. 4.0) ) exit - if( abs(detfer(il)) .le. 100.0 ) then + if( (detmet(il) .lt. 4.2) ) exit + if( abs(detfer(il)) .le. ntol ) then ndet=ndet+1 times(ndet)=((il-1)*nstepsize+NPTS/2)*dt ferrs(ndet)=detfer(il) - snrs(ndet)=12.0*log10(detmet(il))/2-9.0 + snrs(ndet)=12.0*log10(detmet(il)-1)/2-8.0 endif - detmet(max(1,il-5):min(nstep,il+5))=0.0 + detmet(max(1,il-3):min(nstep,il+3))=0.0 ! detmet(il)=0.0 enddo @@ -195,8 +195,9 @@ subroutine detectmsk32(cbig,n,mycall,partnercall,lines,nmessages,nutc,ntol) allmessages=char(0) lines=char(0) - imsgbest=-99 + imsgbest=-1 nbadsyncbest=99 + nhammdbest=99 cdbest=1e32 cdratbest=0.0 @@ -207,7 +208,7 @@ subroutine detectmsk32(cbig,n,mycall,partnercall,lines,nmessages,nutc,ntol) t0=times(ip) cdat=cbig(imid-NPTS/2+1:imid+NPTS/2) ferr=ferrs(ip) - nsnr=snrs(ip) + nsnr=nint(snrs(ip)) ! remove coarse freq error - should now be within a few Hz call tweak1(cdat,NPTS,-(1500+ferr),cdat) @@ -235,7 +236,7 @@ subroutine detectmsk32(cbig,n,mycall,partnercall,lines,nmessages,nutc,ntol) ccr(max(1,ic1-7):min(NPTS-32*6-41,ic1+7))=0.0 enddo - do ipk=1,2 + do ipk=1,3 ! we want ic to be the index of the first sample of the frame ic0=ipeaks(ipk) @@ -283,9 +284,9 @@ subroutine detectmsk32(cbig,n,mycall,partnercall,lines,nmessages,nutc,ntol) if( idf .eq. 0 ) then deltaf=0.0 elseif( mod(idf,2) .eq. 0 ) then - deltaf=4*idf + deltaf=2*idf else - deltaf=-4*(idf+1) + deltaf=-2*(idf+1) endif ! Remove fine frequency error @@ -294,24 +295,14 @@ subroutine detectmsk32(cbig,n,mycall,partnercall,lines,nmessages,nutc,ntol) ! place the beginning of frame at index NSPM+1 cdat2=cshift(cdat2,ic-(NSPM+1)) - do iav=1,8 ! Frame averaging patterns + do iav=1,4 ! Frame averaging patterns if( iav .eq. 1 ) then c=cdat2(NSPM+1:2*NSPM) elseif( iav .eq. 2 ) then - c=cdat2(NSPM-95:NSPM+96) - c=cshift(c,-96) - elseif( iav .eq. 3 ) then - c=cdat2(2*NSPM-95:2*NSPM+96) - c=cshift(c,-96) - elseif( iav .eq. 4 ) then - c=cdat2(1:NSPM) - elseif( iav .eq. 5 ) then - c=cdat2(2*NSPM+1:3*NSPM) - elseif( iav .eq. 6 ) then c=cdat2(1:NSPM)+cdat2(NSPM+1:2*NSPM) - elseif( iav .eq. 7 ) then + elseif( iav .eq. 3 ) then c=cdat2(NSPM+1:2*NSPM)+cdat2(2*NSPM+1:3*NSPM) - elseif( iav .eq. 8 ) then + elseif( iav .eq. 4 ) then c=cdat2(1:NSPM)+cdat2(NSPM+1:2*NSPM)+cdat2(2*NSPM+1:3*NSPM) endif @@ -328,13 +319,11 @@ subroutine detectmsk32(cbig,n,mycall,partnercall,lines,nmessages,nutc,ntol) c=c*conjg(cfac) if( nmatchedfilter .eq. 0 ) then -! sample to get softsamples do i=1, 16 softbits(2*i-1)=imag(c(1+(i-1)*12)) softbits(2*i)=real(c(7+(i-1)*12)) enddo - else -! matched filter - + else ! matched filter softbits(1)=sum(imag(c(1:6))*pp(7:12))+sum(imag(c(NSPM-5:NSPM))*pp(1:6)) softbits(2)=sum(real(c(1:12))*pp) do i=2,16 @@ -343,9 +332,7 @@ subroutine detectmsk32(cbig,n,mycall,partnercall,lines,nmessages,nutc,ntol) enddo endif -! sync word hard error weight is a good discriminator for -! frames that have reasonable probability of decoding - hardbits=0 + hardbits=0 ! use sync word hard error weight to decide whether to send to decoder do i=1, 32 if( softbits(i) .ge. 0.0 ) then hardbits(i)=1 @@ -355,14 +342,13 @@ subroutine detectmsk32(cbig,n,mycall,partnercall,lines,nmessages,nutc,ntol) nbadsync=nbadsync1 if( nbadsync .gt. 3 ) cycle -! normalize the softsymbols before submitting to decoder + ! normalize the softsymbols before submitting to decoder sav=sum(softbits)/32 s2av=sum(softbits*softbits)/32 ssig=sqrt(s2av-sav*sav) softbits=softbits/ssig - if( qsocontext ) then - ! search 32 likely messages only, using correlation discrepancy + if( qsocontext ) then ! search only 32 likely messages. cd=1e6 ihammd=99 do i=0,31 @@ -372,12 +358,13 @@ subroutine detectmsk32(cbig,n,mycall,partnercall,lines,nmessages,nutc,ntol) do ii=1,24 ib=iand(1,ishft(ncw,1-ii)) ib=2*ib-1 - if( ib*softbits(ii+8) .lt. 0 ) cd(i)=cd(i)+abs(softbits(ii+8)) - if( ib*(2*hardbits(ii+8)-1) .lt. 0 ) ihammd(i)=ihammd(i)+1 + if( ib*softbits(ii+8) .lt. 0 ) then + cd(i)=cd(i)+abs(softbits(ii+8)) + ihammd(i)=ihammd(i)+1 + endif enddo enddo - else - ! exhaustive search decoder, using correlation discrepancy + else ! exhaustive decoder, look at every codeword. cd=1e6 ihammd=99 do i=0,4096-1 @@ -387,12 +374,13 @@ subroutine detectmsk32(cbig,n,mycall,partnercall,lines,nmessages,nutc,ntol) do ii=1,24 ib=iand(1,ishft(ncw,1-ii)) ib=2*ib-1 - if( ib*softbits(ii+8) .lt. 0 ) cd(i)=cd(i)+abs(softbits(ii+8)) - if( ib*(2*hardbits(ii+8)-1) .lt. 0 ) ihammd(i)=ihammd(i)+1 + if( ib*softbits(ii+8) .lt. 0 ) then + cd(i)=cd(i)+abs(softbits(ii+8)) + ihammd(i)=ihammd(i)+1 + endif enddo enddo endif - cdm=minval(cd) iloc=minloc(cd) imsg=iloc(1)-1 @@ -401,11 +389,13 @@ subroutine detectmsk32(cbig,n,mycall,partnercall,lines,nmessages,nutc,ntol) iloc=minloc(cd) imsg2=iloc(1)-1 cdrat=cdm2/(cdm+0.001) -! if( cdrat .gt. cdratbest ) then - if( cdm .lt. cdbest ) then + cdrat2=cdm/(cdm2+0.0001) + if( (cdm .lt. cdbest) .or. ((cdm .eq. cdbest) .and. (ihammd(imsg) .lt. nhammdbest)) ) then cdratbest = cdrat + cdrat2best = cdrat2 cdbest = cdm imsgbest = imsg + imsg2best = imsg2 iavbest = iav ipbest = ip ipkbest = ipk @@ -413,23 +403,19 @@ subroutine detectmsk32(cbig,n,mycall,partnercall,lines,nmessages,nutc,ntol) idbest = id iphabest = ipha nbadsyncbest = nbadsync - if( ( ihammd(imsgbest)+nbadsyncbest .le. 4 ) .and. ( (cdratbest .gt. 100.0) .and. (cdbest .le. 0.05) ) ) goto 999 + nhammdbest = ihammd(imsg) + if( ( nhammdbest .eq. 0 ) .and. (cdbest .eq. 0.0) .and. (cdratbest .gt. 2000.0) ) goto 999 endif enddo ! phase loop enddo ! frame averaging loop enddo ! frequency dithering loop - enddo ! sample-time dither loop - enddo ! peak loop - -! write(78,1001) nutc,t0,nsnr,ic,ipk,is,idf,iav,deltaf,fest,ferr,ferr2,ffin,bba,bbp,nbadsync, & -! phase0,msgreceived -! call flush(78) -!1001 format(i6.6,f8.2,i5,i5,i5,i5,i5,i5,f8.2,f8.2,f8.2,f8.2,f8.2,f10.2,f8.2,i5,f8.2,2x,a22) - enddo + enddo ! slicer dither loop + enddo ! time-sync correlation-peak loop + enddo ! candidate loop 999 continue msgreceived=' ' if( imsgbest .gt. 0 ) then - if( ( ihammd(imsgbest)+nbadsyncbest .le. 4 ) .and. (cdratbest .gt. 50.0) .and. (cdbest .le. 0.05) ) then + if( ( nhammdbest+nbadsyncbest .le. 4 ) .and. cdratbest .gt. 10.0 ) then if( qsocontext ) then nrxrpt=iand(likelymessages(imsgbest),31) nrxhash=(likelymessages(imsgbest)-nrxrpt)/32 @@ -452,11 +438,11 @@ subroutine detectmsk32(cbig,n,mycall,partnercall,lines,nmessages,nutc,ntol) 1020 format(i6.6,i4,f5.1,i5,' & ',a22) ! write(*,1022) nutc,ipbest,times(ipbest),snrs(ipbest),fest,nrxrpt,nrxhash, & -! rpt(nrxrpt),imessage,ig24(imessage),ihammd(imsgbest), & -! cdbest,cdratbest,nbadsyncbest,ipkbest,idbest,idfbest,iavbest,iphabest +! rpt(nrxrpt),imessage,ig24(imessage),nhammdbest, & +! cdbest,cdratbest,cdrat2best,nbadsyncbest,ipkbest,idbest,idfbest,iavbest,iphabest endif endif endif -!1022 format(i4.4,2x,i4,f8.3,f8.2,f8.2,i6,i6,a6,i8,i10,i4,f8.2,f8.2,i5,i5,i5,i5,i5,i5) +1022 format(i4.4,2x,i4,f8.3,f8.2,f8.2,i6,i6,a6,i8,i10,i4,f8.3,f8.2,f8.2,i5,i5,i5,i5,i5,i5) return end subroutine detectmsk32