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Tweaks to msk32 decoder. 

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6902 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
This commit is contained in:
Steven Franke 2016-07-10 02:19:43 +00:00
parent cbe49a8297
commit d7dfb906e1
1 changed files with 39 additions and 53 deletions
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92
lib/detectmsk32.f90
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@ -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