From 06790698781c7b95297c751333ff25bd995e14f3 Mon Sep 17 00:00:00 2001
From: Steven Franke <s.j.franke@icloud.com>
Date: Thu, 9 Jun 2016 02:02:50 +0000
Subject: [PATCH] Added msk144dt; tweaks to syncmsk144l

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6743 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
---
 lib/msk144_decode.f90 | 27 +++++++++++++++------------
 lib/mskdt.f90         |  3 +--
 lib/syncmsk144.f90    | 40 ++++++++++++++++++++--------------------
 3 files changed, 36 insertions(+), 34 deletions(-)

diff --git a/lib/msk144_decode.f90 b/lib/msk144_decode.f90
index ea5eafbe3..8f79969a0 100644
--- a/lib/msk144_decode.f90
+++ b/lib/msk144_decode.f90
@@ -39,9 +39,9 @@ subroutine msk144_decode(id2,npts,nutc,nprint,line)
 !### Would it be better to set median rms to 1.0 ?
 !  d(0:npts-1)=d(0:npts-1)/rms          !Normalize so that rms=1.0
 
-  call mskdt(d,npts,ty,yellow,nyel)
+  call msk144dt(d,npts,ty,yellow,nyel)
 
-  nyel=min(nyel,100)
+  nyel=min(nyel,20)
 
   n=log(float(npts))/log(2.0) + 1.0
   nfft=min(2**n,1024*1024)
@@ -58,21 +58,24 @@ subroutine msk144_decode(id2,npts,nutc,nprint,line)
      iz=ib-ia+1
      cdat2(1:iz)=c(ia:ib)               !Select nlen complex samples
      t0=ia/12000.0
-     call syncmsk144(cdat2,iz,msg,freq)
+     call syncmsk144(cdat2,iz,msg,freq,nutc,t0)
      if(msg(1:1).ne.' ') then
-!      if(msg.ne.msg0) then
+       if(msg.ne.msg0) then
          nline=nline+1
          nsnr0=-99
-!      endif
-       y=10.0**(0.1*(yellow(n)-1.5))
-       nsnr=max(-5,nint(db(y)))
-!      if(nsnr.gt.nsnr0 .and. nline.gt.0) then
+       endif
+!       y=10.0**(0.1*(yellow(n)-1.5))
+!       nsnr=max(-5,nint(db(y)))
+      y=yellow(n)-1.5
+      nsnr=y*10   ! this should be 10*db (centibels?)
+      if( nsnr .gt. 999 ) nsnr=99
+      if(nsnr.gt.nsnr0 .and. nline.gt.0) then
       write(line(nline),1020) nutc,nsnr,t0,nint(freq),msg
       if(nprint.ne.0) write(*,1020) nutc,nsnr,t0,nint(freq),msg
-1020   format(i6.6,i4,f5.1,i5,' & ',a22)
-       nsnr0=nsnr
-!      go to 900
-!    endif
+1020  format(i6.6,i4,f5.1,i5,' & ',a22)
+      nsnr0=nsnr
+      go to 900
+     endif
      msg0=msg
      endif
   enddo
diff --git a/lib/mskdt.f90 b/lib/mskdt.f90
index 77ba0215e..bca835996 100644
--- a/lib/mskdt.f90
+++ b/lib/mskdt.f90
@@ -62,8 +62,7 @@ subroutine mskdt(d,npts,ty,yellow,nyel)
   do j=2,nyel
      ok=.true.
      do i=1,j-1
-!        if(abs(ty(i)-ty(j)).lt.0.117) ok=.false.
-        if(abs(ty(i)-ty(j)).lt.0.072) ok=.false.  ! does this break jtmsk?
+        if(abs(ty(i)-ty(j)).lt.0.117) ok=.false.
      enddo
      if(ok) then
         k=k+1
diff --git a/lib/syncmsk144.f90 b/lib/syncmsk144.f90
index 1fe40b24f..42dbd21e6 100644
--- a/lib/syncmsk144.f90
+++ b/lib/syncmsk144.f90
@@ -1,4 +1,4 @@
-subroutine syncmsk144(cdat,npts,msgreceived,fest)
+subroutine syncmsk144(cdat,npts,msgreceived,fest,nutc,t0)  !nutc and t0 are for debug output 
   use iso_c_binding, only: c_loc,c_size_t
   use packjt
   use hashing
@@ -107,6 +107,10 @@ subroutine syncmsk144(cdat,npts,msgreceived,fest)
     endif
   else   
     msgreceived=' '
+    phase0=-97      !-97 is failed carrier sync, -98 failure to decode, -99 decoded, bad hash
+    niterations=0
+    ndither=0
+    i1hashdec=0
     goto 999 
   endif
  
@@ -174,15 +178,6 @@ subroutine syncmsk144(cdat,npts,msgreceived,fest)
   if( ic .le. 864 ) ic=ic+864
   if( ic .gt. 2*864 ) ic=ic-864
 
-! Sanity check - recompute bb and verify that peak is now at designated lag.
-!  do i=1,6
-!   io=i-3
-!   bb(i) = sum( ( cdat(ic+io:ic+io+864:6) * conjg( cdat(ic+io+6:ic+io+6+864:6) ) )*2 )
-!  enddo
-!  iloc=maxloc(abs(bb))
-!  ibb=iloc(1)
-! write(*,*) 'ic1: ',ic,'bb peak is at : ',ibb
-
 ! Estimate fine frequency error. 
 ! Should a larger separation be used when frames are averaged?
   cca=sum(cdat(ic:ic+41)*conjg(cb))
@@ -238,11 +233,10 @@ subroutine syncmsk144(cdat,npts,msgreceived,fest)
   enddo 
 
 ! calculated the number of sync-word bits that are incorrect
-! this might come in handy some day
-  nbadsync=sum(s8*(2*hardbits(1:8)-1))
-  nbadsync=nbadsync+sum(s8*(2*hardbits(57:57+7)-1))
-  nbadsync=16-nbadsync
-
+! 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
+  nbadsync=nbadsync1+nbadsync2
   if( nbadsync .gt. 6 ) cycle
 
 ! this could be used to count the number of hard errors that were corrected
@@ -257,7 +251,8 @@ subroutine syncmsk144(cdat,npts,msgreceived,fest)
   ssig=sqrt(s2av-sav*sav)
   softbits=softbits/ssig
 
-  sigma=0.65
+! sigma=0.65
+  sigma=0.70
   lratio(1:48)=softbits(9:9+47)
   lratio(49:128)=softbits(65:65+80-1)
   lratio=exp(2.0*lratio/(sigma*sigma))
@@ -266,7 +261,7 @@ subroutine syncmsk144(cdat,npts,msgreceived,fest)
   unscrambledsoftbits(2:128:2)=lratio(65:128) 
 
   max_iterations=10
-  max_dither=100
+  max_dither=50
   call ldpc_decode(unscrambledsoftbits, decoded, max_iterations, niterations, max_dither, ndither)
 
   if( niterations .ge. 0.0 ) then
@@ -278,6 +273,8 @@ enddo
 enddo
 
 msgreceived=' '
+phase0=-98
+i1hashdec=0
 goto 999
 
 778 continue
@@ -310,10 +307,13 @@ goto 999
       call unpackmsg(i4Dec6BitWords,msgreceived)
     else
       msgreceived=' '
+      phase0=-99
     endif
 
-write(78,1001) iav,ipk,is,fdiff,fest,nbadsync,phase0,niterations,ndither,i1hashdec,i1Dec8BitBytes(10),msgreceived
-1001 format(i6,i6,i6,f10.1,f10.1,i6,f10.2,i6,i6,i6,i6,4x,a22)
-999 return
+999 continue
+    write(78,1001) nutc,t0,iav,ipk,is,fdiff,fest,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)
 
+    return
 end subroutine syncmsk144