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First-cut at decoder for (32,16) msk32. Needs more work.

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git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6954 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
This commit is contained in:
Steven Franke 2016-07-27 14:40:38 +00:00
parent 217257df58
commit aeed9e3344
2 changed files with 80 additions and 285 deletions
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361
lib/detectmsk32.f90
View File

@ -1,56 +1,34 @@
subroutine detectmsk32(cbig,n,mycall,partnercall,lines,nmessages,nutc,ntol,t00)
use timer_module, only: timer
parameter (NSPM=192, NPTS=3*NSPM, MAXSTEPS=7500, NFFT=3*NSPM, MAXCAND=40)
character*4 rpt(0:31)
parameter (NSPM=192, NPTS=3*NSPM, MAXSTEPS=7500, NFFT=3*NSPM, MAXCAND=10)
character*4 rpt(0:63)
character*6 mycall,partnercall
character*22 hashmsg,msgreceived,allmessages(20)
character*22 msg,msgsent,msgreceived,allmessages(32)
character*80 lines(100)
complex bb(6)
complex cbig(n)
complex cdat(NPTS) !Analytic signal
complex cdat2(NPTS)
complex c(NSPM)
complex ctmp(NFFT)
complex cb(42) !Complex waveform for sync word
complex cbr(42) !Complex waveform for reversed sync word
complex cfac,cca,ccb
complex ccr(NPTS)
complex ccr1(NPTS)
complex ccr2(NPTS)
complex bb(6)
integer s8(8),s8r(8),hardbits(32)
complex ctmp(NPTS) !Analytic signal
complex cft(512)
complex cwaveforms(192,64)
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 itone(144)
logical ismask(NFFT)
real cbi(42),cbq(42)
real detmet(-2:MAXSTEPS+3)
real detfer(MAXSTEPS)
real rcw(12)
real ddr(NPTS)
real ferrs(MAXCAND)
real pp(12) !Half-sine pulse shape
real pp(12)
real rcw(12)
real snrs(MAXCAND)
real times(MAXCAND)
real tonespec(NFFT)
real*8 dt, df, fs, pi, twopi
real softbits(32)
logical first
data first/.true./
data s8/0,1,1,1,0,0,1,0/
data s8r/1,0,1,1,0,0,0,1/
data rpt /'-04 ','-02 ','+00 ','+02 ','+04 ','+06 ','+08 ','+10 ','+12 ', &
'+14 ','+16 ','+18 ','+20 ','+22 ','+24 ', &
'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,nhashes,pi,twopi,dt,s8,rcw,pp,nmatchedfilter,ig24
save df,first,cb,cbr,fs,nhashes,pi,twopi,dt,rcw,pp,nmatchedfilter,cwaveforms,rpt
if(first) then
nmatchedfilter=1
@ -67,43 +45,42 @@ subroutine detectmsk32(cbig,n,mycall,partnercall,lines,nmessages,nutc,ntol,t00)
rcw(i)=(1-cos(angle))/2
enddo
! define the sync word waveforms
s8=2*s8-1
cbq(1:6)=pp(7:12)*s8(1)
cbq(7:18)=pp*s8(3)
cbq(19:30)=pp*s8(5)
cbq(31:42)=pp*s8(7)
cbi(1:12)=pp*s8(2)
cbi(13:24)=pp*s8(4)
cbi(25:36)=pp*s8(6)
cbi(37:42)=pp(1:6)*s8(8)
cb=cmplx(cbi,cbq)
s8r=2*s8r-1
cbq(1:6)=pp(7:12)*s8r(1)
cbq(7:18)=pp*s8r(3)
cbq(19:30)=pp*s8r(5)
cbq(31:42)=pp*s8r(7)
cbi(1:12)=pp*s8r(2)
cbi(13:24)=pp*s8r(4)
cbi(25:36)=pp*s8r(6)
cbi(37:42)=pp(1:6)*s8r(8)
cbr=cmplx(cbi,cbq)
call golay24_table(ig24)
do i=0,4095
ncw=ig24(i)
do j=0,23
ib=iand(1,ishft(ncw,-j))
ig(j,i)=2*ib-1
enddo
do i=0,30
if( i.lt.5 ) then
write(rpt(i),'(a1,i2.2,a1)') '-',abs(i-5)
write(rpt(i+31),'(a2,i2.2,a1)') 'R-',abs(i-5)
else
write(rpt(i),'(a1,i2.2,a1)') '+',i-5
write(rpt(i+31),'(a2,i2.2,a1)') 'R+',i-5
endif
enddo
rpt(62)='RRR '
rpt(63)='73 '
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)
dphi0=twopi*(freq-500)/12000.0
dphi1=twopi*(freq+500)/12000.0
do i=1,64
msg='<'//trim(mycall)//' '//trim(partnercall)//'> '//rpt(i-1)
call genmsk32(msg,msgsent,0,itone,itype)
! write(*,*) i,msg,msgsent,itype
nsym=32
phi=0.0
indx=1
nreps=1
do jrep=1,nreps
do isym=1,nsym
if( itone(isym) .eq. 0 ) then
dphi=dphi0
else
dphi=dphi1
endif
do j=1,6
cwaveforms(indx,i)=cmplx(cos(phi),sin(phi));
indx=indx+1
phi=mod(phi+dphi,twopi)
enddo
enddo
enddo
enddo
first=.false.
@ -186,24 +163,16 @@ subroutine detectmsk32(cbig,n,mycall,partnercall,lines,nmessages,nutc,ntol,t00)
! 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
nmessages=0
allmessages=char(0)
lines=char(0)
fbest=1e6
pkbest=-1e6
imsgbest=-1
nbadsyncbest=99
nhammdbest=99
icdbest=1e6
cdratbest=0.0
istartbest=-1
ipbest=-1
nsnrbest=-100
t0best=-1e6
do ip=1,ndet !run through the candidates and try to sync/demod/decode
imid=times(ip)*fs
if( imid .lt. NPTS/2 ) imid=NPTS/2
@ -215,216 +184,42 @@ 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
call tweak1(cdat,NPTS,-(1500+ferr),cdat)
! attempt frame synchronization
! correlate with sync word waveforms
ccr=0
ccr1=0
ccr2=0
do i=1,NPTS-(32*6+41)
ccr1(i)=sum(cdat(i:i+41)*conjg(cbr))
ccr2(i)=sum(cdat(i+32*6:i+32*6+41)*conjg(cbr))
enddo
ccr=ccr1+ccr2
ddr=abs(ccr1)*abs(ccr2)
crmax=maxval(abs(ccr))
! Find 6 largest peaks
do ipk=1,6
iloc=maxloc(abs(ccr))
ic1=iloc(1)
iloc=maxloc(ddr)
ic2=iloc(1)
ipeaks(ipk)=ic1
ccr(max(1,ic1-7):min(NPTS-32*6-41,ic1+7))=0.0
enddo
do ipk=1,3
! we want ic to be the index of the first sample of the frame
ic0=ipeaks(ipk)
! fine adjustment of sync index
do i=1,6
if( ic0+11+NSPM .le. NPTS ) then
bb(i) = sum( ( cdat(ic0+i-1+6:ic0+i-1+6+NSPM:6) * conjg( cdat(ic0+i-1:ic0+i-1+NSPM:6) ) )**2 )
else
bb(i) = sum( ( cdat(ic0+i-1+6:NPTS:6) * conjg( cdat(ic0+i-1:NPTS-6:6) ) )**2 )
do imsg=1,64
do istart=NSPM-NSPM/2,NPTS-NSPM
cft(1:144)=cdat(istart:istart+144-1)*conjg(cwaveforms(1:144,imsg))
cft(145:512)=0.
df=12000.0/512.0
call four2a(cft,512,1,-1,1)
iloc=maxloc(abs(cft))
ipk=iloc(1)
pk=abs(cft(ipk))
fpk=(ipk-1)*df
if( fpk.gt.12000.0 ) fpk=fpk-12000.0
if( pk .gt. pkbest .and. abs(fpk-1500.0) .le. ntol) then
ipbest=ip
pkbest=pk
fbest=fpk
imsgbest=imsg
istartbest=istart
nsnrbest=nsnr
t0best=t0
endif
enddo
iloc=maxloc(abs(bb))
ibb=iloc(1)
bba=abs(bb(ibb))
bbp=atan2(-imag(bb(ibb)),-real(bb(ibb)))/(2*twopi*6*dt)
if( ibb .le. 3 ) ibb=ibb-1
if( ibb .gt. 3 ) ibb=ibb-7
enddo
do id=1,1 ! slicer dither.
if( id .eq. 1 ) is=0
if( id .eq. 2 ) is=-1
if( id .eq. 3 ) is=1
! Adjust frame index to place peak of bb at desired lag
ic=ic0+ibb+is
if( ic .lt. 1 ) ic=ic+NSPM
! Estimate fine frequency error.
cca=sum(cdat(ic:ic+41)*conjg(cb))
if( ic+32*6+41 .le. NPTS ) then
ccb=sum(cdat(ic+32*6:ic+32*6+41)*conjg(cb))
cfac=ccb*conjg(cca)
ferr2=atan2(imag(cfac),real(cfac))/(twopi*32*6*dt)
else
ccb=sum(cdat(ic-32*6:ic-32*6+41)*conjg(cb))
cfac=cca*conjg(ccb)
ferr2=atan2(imag(cfac),real(cfac))/(twopi*32*6*dt)
endif
! 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
elseif( mod(idf,2) .eq. 0 ) then
deltaf=2*idf
else
deltaf=-2*(idf+1)
endif
! Remove fine frequency error
call tweak1(cdat,NPTS,-(ferr2+deltaf),cdat2)
! place the beginning of frame at index NSPM+1
cdat2=cshift(cdat2,ic-(NSPM+1))
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(1:NSPM)+cdat2(NSPM+1:2*NSPM)
elseif( iav .eq. 3 ) then
c=cdat2(NSPM+1:2*NSPM)+cdat2(2*NSPM+1:3*NSPM)
elseif( iav .eq. 4 ) then
c=cdat2(1:NSPM)+cdat2(NSPM+1:2*NSPM)+cdat2(2*NSPM+1:3*NSPM)
endif
! Estimate final frequency error and carrier phase.
cca=sum(c(1:1+41)*conjg(cb))
phase0=atan2(imag(cca),real(cca))
do ipha=1,3
if( ipha.eq.2 ) phase0=phase0-20*pi/180.0
if( ipha.eq.3 ) phase0=phase0+20*pi/180.0
! Remove phase error - want constellation rotated so that sample points lie on I/Q axes
cfac=cmplx(cos(phase0),sin(phase0))
c=c*conjg(cfac)
if( nmatchedfilter .eq. 0 ) then
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
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
softbits(2*i-1)=sum(imag(c(1+(i-1)*12-6:1+(i-1)*12+5))*pp)
softbits(2*i)=sum(real(c(7+(i-1)*12-6:7+(i-1)*12+5))*pp)
enddo
endif
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
endif
enddo
nbadsync1=(8-sum( (2*hardbits(1:8)-1)*s8r ) )/2
nbadsync=nbadsync1
if( nbadsync .gt. 5 ) cycle
! normalize the softsymbols before submitting to decoder
sav=sum(softbits)/32
s2av=sum(softbits*softbits)/32
ssig=sqrt(s2av-sav*sav)
softbits=softbits/ssig
isoftbits=softbits*1e4
call timer('search32',0)
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
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=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
enddo ! slicer dither loop
enddo ! time-sync correlation-peak loop
enddo ! candidate loop
999 continue
msgreceived=' '
if( imsgbest .gt. 0 ) 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
if( imsgbest .gt. 0 .and. pkbest .ge. 108.0) then
nrxrpt=iand(imsgbest-1,63)
nrxhash=(imsgbest-1-nrxrpt)/64
!write(*,*) ipbest,pkbest,fbest,imsgbest,istartbest,nsnrbest,t0best,nrxrpt,nrxhash
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
write(lines(nmessages),1020) nutc,nsnrbest,t0best,nint(fbest),msgreceived
1020 format(i6.6,i4,f5.1,i5,' & ',a22)
! write(*,1022) nutc,ipbest,times(ipbest),snrs(ipbest),fest,nrxrpt,nrxhash,nhashes(nrxrpt), &
! rpt(nrxrpt),imessage,ig24(imessage),nhammdbest, &
! 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

4
lib/genmsk32.f90
View File

@ -10,7 +10,7 @@ subroutine genmsk32(msg,msgsent,ichk,itone,itype)
integer*1 s8r(8)
data s8r/1,0,1,1,0,0,0,1/
data first/.true./
save first,ig32
save first,rpt,ig32
if(first) then
call ldpc32_table(ig32) !Define the Golay(24,12) codewords
@ -52,7 +52,7 @@ subroutine genmsk32(msg,msgsent,ichk,itone,itype)
ncodeword=ig32(ig)
write(*,*) 'codeword is: ',ncodeword,'message is: ',ig,'report index: ',irpt,'hash: ',ihash
! write(*,*) 'codeword is: ',ncodeword,'message is: ',ig,'report index: ',irpt,'hash: ',ihash
do i=1,32
codeword(i)=iand(1,ishft(ncodeword,1-i))