From b91a9a782b889baa6d660ca46835377f818dc31d Mon Sep 17 00:00:00 2001 From: Steven Franke Date: Sat, 11 Jun 2016 02:39:21 +0000 Subject: [PATCH] Tweaks to syncmsk144 - improve performance for short pings. git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6758 ab8295b8-cf94-4d9e-aec4-7959e3be5d79 --- lib/syncmsk144.f90 | 140 +++++++++++++++++++++++++++++---------------- 1 file changed, 90 insertions(+), 50 deletions(-) diff --git a/lib/syncmsk144.f90 b/lib/syncmsk144.f90 index cbe4546f1..fbcf60c29 100644 --- a/lib/syncmsk144.f90 +++ b/lib/syncmsk144.f90 @@ -109,6 +109,10 @@ subroutine syncmsk144(cdat,npts,pchk_file,msgreceived,fest,nutc,t0) niterations=0 ndither=0 i1hashdec=0 + fest=0.0 + i1Dec8BitBytes=0 + nbadsync1=-1 + nbadsync2=-1 goto 999 endif @@ -140,70 +144,102 @@ subroutine syncmsk144(cdat,npts,pchk_file,msgreceived,fest,nutc,t0) ! See if we can find "closed brackets" - a pair of peaks that differ by 864, plus or minus ! This information is not yet used for anything - do ii=1,5 - do jj=ii+1,5 - if( (ii .ne. jj) .and. (abs( abs(ipeaks(ii)-ipeaks(jj))-864) .le. 5) ) then +! do ii=1,5 +! do jj=ii+1,5 +! if( (ii .ne. jj) .and. (abs( abs(ipeaks(ii)-ipeaks(jj))-864) .le. 5) ) then ! write(*,*) "closed brackets: ",ii,jj,ipeaks(ii),ipeaks(jj),abs(ipeaks(ii)-ipeaks(jj)) - endif - enddo - enddo +! endif +! enddo +! enddo - do iav=1,6 do ipk=1,5 - do id=1,3 - if( id .eq. 1 ) is=0 - if( id .eq. 2 ) is=-1 - if( id .eq. 3 ) is=1 -! we want ic to be the index of the first sample of the message - ic=ipeaks(ipk) +! we want ic to be the index of the first sample of the frame + ic0=ipeaks(ipk) - if( ic .le. 864 ) ic=ic+864 - if( ic .gt. 2*864 ) ic=ic-864 -! now do fine adjustment of sync index -! bb is used to place the sampling index at the center of the eye +! fine adjustment of sync index +! bb lag used to place the sampling index at the center of the eye do i=1,6 - io=i-3 - ill=max(1,ic+io) - iul=min(ic+io+6+864,npts) - bb(i) = sum( ( cdat(ic+io:iul-6:6) * conjg( cdat(ic+io+6:iul:6) ) )*2 ) + 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 ) + endif enddo iloc=maxloc(abs(bb)) ibb=iloc(1) - + bba=abs(bb(ibb)) + if( ibb .le. 3 ) ibb=ibb-1 + if( ibb .gt. 3 ) ibb=ibb-7 + do id=1,3 ! 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=ic + ibb-2+is - if( ic .le. 864 ) ic=ic+864 - if( ic .gt. 2*864 ) ic=ic-864 + ic=ic0+ibb+is + if( ic .lt. 1 ) ic=ic+864 ! Estimate fine frequency error. ! Should a larger separation be used when frames are averaged? cca=sum(cdat(ic:ic+41)*conjg(cb)) - ccb=sum(cdat(ic+56*6:ic+56*6+41)*conjg(cb)) - cfac=ccb*conjg(cca) - ferr2=atan2(imag(cfac),real(cfac))/(twopi*56*6*dt) + if( ic+56*6+41 .le. npts ) then + ccb=sum(cdat(ic+56*6:ic+56*6+41)*conjg(cb)) + cfac=ccb*conjg(cca) + ferr2=atan2(imag(cfac),real(cfac))/(twopi*56*6*dt) + else + ccb=sum(cdat(ic-88*6:ic-88*6+41)*conjg(cb)) + cfac=cca*conjg(ccb) + ferr2=atan2(imag(cfac),real(cfac))/(twopi*88*6*dt) + endif ! Final estimate of the carrier frequency - returned to the calling program fest=1500+ferr+ferr2 ! Remove fine frequency error call tweak1(cdat,npts,-ferr2,cdat2) -! place the beginning of the central frame at NSPM+1 - cdat2=cshift(cdat2,ic-865) +! place the beginning of frame at index NSPM+1 + cdat2=cshift(cdat2,ic-(NSPM+1)) + do iav=1,7 ! Try each of the three frames individually, and then ! do frame averaging on passes 4 and 5 +if( 0 .eq. 1 ) then if( iav .eq. 1 ) then - c=cdat2(NSPM+1:2*NSPM) - elseif( iav .eq. 2 ) then - c=cdat2(2*NSPM+1:npts) - elseif( iav .eq. 3 ) then c=cdat2(1:NSPM) + elseif( iav .eq. 2 ) then + c=cdat2(NSPM+1:2*NSPM) + elseif( iav .eq. 3 ) then + c=cdat2(2*NSPM+1:npts) elseif( iav .eq. 4 ) then c=cdat2(1:NSPM)+cdat2(NSPM+1:2*NSPM) elseif( iav .eq. 5 ) then - c=cdat2(NSPM+1:2*NSPM)+cdat2(2*NSPM+1:npts) + c=cdat2(1:NSPM)+cdat2(NSPM+1:2*NSPM) elseif( iav .eq. 6 ) then + c=cdat2(1:NSPM)+cdat2(NSPM+1:2*NSPM) + elseif( iav .eq. 7 ) then + c=cdat2(1:NSPM)+cdat2(NSPM+1:2*NSPM) + elseif( iav .eq. 8 ) then + c=cdat2(NSPM+1:2*NSPM)+cdat2(2*NSPM+1:npts) + elseif( iav .eq. 9 ) then + c=cdat2(1:NSPM)+cdat2(NSPM+1:2*NSPM)+cdat2(2*NSPM+1:npts) + endif +endif + + if( iav .eq. 1 ) then + c(1:NSPM)=cdat2(NSPM+1:2*NSPM) !avg 1 frame to the right of ic + elseif( iav .eq. 2 ) then + c=cdat2(NSPM-431:NSPM+432) !1 frame centered on ic + c=cshift(c,-432) + elseif( iav .eq. 3 ) then !1 frame to the left of ic + c=cdat2(1:NSPM) + elseif( iav .eq. 4 ) then + c=cdat2(NSPM+432:NSPM+432+863) !1 frame beginning 36ms to the right of ic + c=cshift(c,432) + elseif( iav .eq. 5 ) then + c=cdat2(1:NSPM)+cdat2(NSPM+1:2*NSPM) + elseif( iav .eq. 6 ) then + c=cdat2(NSPM+1:2*NSPM)+cdat2(2*NSPM+1:npts) + elseif( iav .eq. 7 ) then c=cdat2(1:NSPM)+cdat2(NSPM+1:2*NSPM)+cdat2(2*NSPM+1:npts) endif @@ -214,28 +250,33 @@ subroutine syncmsk144(cdat,npts,pchk_file,msgreceived,fest,nutc,t0) ffin=atan2(imag(cfac),real(cfac))/(twopi*56*6*dt) phase0=atan2(imag(cca+ccb),real(cca+ccb)) -! Remove the static phase error from the data cfac=cmplx(cos(phase0),sin(phase0)) c=c*conjg(cfac) ! sample to get softsamples - do i=1,72 - softbits(2*i-1)=imag(c(1+(i-1)*12)) - softbits(2*i)=real(c(7+(i-1)*12)) +! do i=1,72 +! softbits(2*i-1)=imag(c(1+(i-1)*12)) +! softbits(2*i)=real(c(7+(i-1)*12)) +! enddo + +! matched filter + softbits(1)=sum(imag(c(1:6))*pp(7:12))+sum(imag(c(864-5:864))*pp(1:6)) + softbits(2)=sum(real(c(1:12))*pp) + do i=2,72 + 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 + hardbits=0 do i=1,144 if( softbits(i) .ge. 0.0 ) then hardbits(i)=1 endif enddo - -! calculated the number of sync-word bits that are incorrect -! don't present to the decoder if there are too many sync-word bit-errors - nbadsync1=(8-sum(s8*(2*hardbits(1:8)-1)))/2 - nbadsync2=(8-sum(s8*(2*hardbits(57:57+7)-1)))/2 + nbadsync1=(8-sum( (2*hardbits(1:8)-1)*s8 ) )/2 + nbadsync2=(8-sum( (2*hardbits(1+56:8+56)-1)*s8 ) )/2 nbadsync=nbadsync1+nbadsync2 - if( nbadsync .gt. 6 ) cycle + if( nbadsync .gt. 4 ) cycle ! this could be used to count the number of hard errors that were corrected hardword(1:48)=hardbits(9:9+47) @@ -249,8 +290,7 @@ subroutine syncmsk144(cdat,npts,pchk_file,msgreceived,fest,nutc,t0) ssig=sqrt(s2av-sav*sav) softbits=softbits/ssig -! sigma=0.65 - sigma=0.70 + sigma=0.65 lratio(1:48)=softbits(9:9+47) lratio(49:128)=softbits(65:65+80-1) lratio=exp(2.0*lratio/(sigma*sigma)) @@ -258,7 +298,7 @@ subroutine syncmsk144(cdat,npts,pchk_file,msgreceived,fest,nutc,t0) unscrambledsoftbits(1:127:2)=lratio(1:64) unscrambledsoftbits(2:128:2)=lratio(65:128) - max_iterations=10 + max_iterations=20 max_dither=50 call ldpc_decode(unscrambledsoftbits, decoded, max_iterations, niterations, max_dither, ndither) @@ -309,9 +349,9 @@ goto 999 endif 999 continue -! write(78,1001) nutc,t0,iav,ipk,is,fdiff,fest,nbadsync1,nbadsync2, & +! write(78,1001) nutc,t0,iav,ipk,is,fdiff,fest,ffin,nbadsync1,nbadsync2, & ! phase0,niterations,ndither,i1hashdec,i1Dec8BitBytes(10),msgreceived -!1001 format(i6,f8.2,i4,i4,i4,f8.2,f8.2,i4,i4,f8.2,i4,i4,i4,i4,2x,a22) +!1001 format(i6,f8.2,i4,i4,i4,f8.2,f8.2,f8.2,i4,i4,f8.2,i4,i4,i4,i4,2x,a22) return end subroutine syncmsk144