From ad0ad1680b420976e80fd0adc1176214cfd078de Mon Sep 17 00:00:00 2001
From: Steven Franke <s.j.franke@icloud.com>
Date: Sun, 23 Oct 2016 17:37:44 +0000
Subject: [PATCH] Tweaks to decrease UER for Sh messages.

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@7221 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
---
 lib/ldpcsim40.f90        | 11 ++++++-----
 lib/msk144d2.f90         |  9 ++++++---
 lib/msk40decodeframe.f90 |  5 +++--
 lib/msk40spd.f90         |  4 ++--
 4 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/lib/ldpcsim40.f90 b/lib/ldpcsim40.f90
index 27a51dd88..9860f7f10 100644
--- a/lib/ldpcsim40.f90
+++ b/lib/ldpcsim40.f90
@@ -27,16 +27,17 @@ read(arg,*) ntrials
 call getarg(4,arg)
 read(arg,*) s
 
-rate=real(K)/real(N)
+n=32
+!rate=real(K)/real(N)
 ! don't count hash bits as data bits
-!rate=5.0/real(N)
+rate=4.0/real(N)
 write(*,*) "rate: ",rate
 write(*,*) "niter= ",max_iterations," ndither= ",max_dither," s= ",s
 
 allocate ( codeword(N), decoded(K), message(K) )
 allocate ( lratio(N), rxdata(N), llr(N) )
 
-msg="K1JT K9AN RRR         "
+msg="K1JT K9AN"
 irpt=14
 call hash(msg,22,ihash)
 ihash=iand(ihash,4095)                 !12-bit hash
@@ -52,8 +53,8 @@ write(*,'(32i1)') codeword
 call init_random_seed()
 
 write(*,*) "Eb/N0  SNR2500   ngood  nundetected nbadhash"
-do idb = -6, 14
-  db=idb/2.0-1.0
+do idb = 0, 30
+  db=idb/2.0
   sigma=1/sqrt( 2*rate*(10**(db/10.0)) )
   ngood=0
   nue=0
diff --git a/lib/msk144d2.f90 b/lib/msk144d2.f90
index 51d974658..268ac2fed 100644
--- a/lib/msk144d2.f90
+++ b/lib/msk144d2.f90
@@ -94,9 +94,12 @@ program msk144d2
      do i=1,npts-7*1024+1,7*512
        ichunk=id2(i:i+7*1024-1)
        tsec=(i-1)/12000.0
-       call mskrtd(ichunk,nutc,tsec,ntol,nrxfreq,ndepth,mycall,hiscall,bShMsgs,line)
-       if( index(line,"^") .ne. 0 .or. index(line,"&") .ne. 0 ) then
-         write(*,*) line
+       tt=sum(float(abs(id2(i:i+7*512-1))))
+       if( tt .ne. 0.0 ) then
+         call mskrtd(ichunk,nutc,tsec,ntol,nrxfreq,ndepth,mycall,hiscall,bShMsgs,line)
+         if( index(line,"^") .ne. 0 .or. index(line,"&") .ne. 0 ) then
+           write(*,*) line
+         endif
        endif
      enddo 
   enddo
diff --git a/lib/msk40decodeframe.f90 b/lib/msk40decodeframe.f90
index 79bd2a036..15e832c33 100644
--- a/lib/msk40decodeframe.f90
+++ b/lib/msk40decodeframe.f90
@@ -100,7 +100,8 @@ subroutine msk40decodeframe(c,mycall,hiscall,xsnr,msgreceived,nsuccess)
   softbits=softbits/ssig
 
   sigma=0.75
-  if(xsnr.lt.0.0) sigma=0.75-0.0875*xsnr
+!  if(xsnr.lt.0.0) sigma=0.75-0.0875*xsnr
+  if(xsnr.lt.0.0) sigma=0.75-0.11*xsnr
   llr(1:32)=softbits(9:40)
   llr=2.0*llr/(sigma*sigma)
   
@@ -124,8 +125,8 @@ subroutine msk40decodeframe(c,mycall,hiscall,xsnr,msgreceived,nsuccess)
     enddo
     nrxrpt=iand(imsg,15)
     nrxhash=(imsg-nrxrpt)/16
+    if(nhammd.le.4 .and. cord .lt. 0.65 .and. nrxhash.eq.ihash) then
 !write(*,*) 'decodeframe ',nhammd,cord,nrxhash,nrxrpt,ihash,xsnr,sigma
-    if(nhammd.le.5 .and. cord .lt. 1.7 .and. nrxhash.eq.ihash) then
       nsuccess=1    
       write(msgreceived,'(a1,a,1x,a,a1,1x,a4)') "<",trim(mycall),   &
                                     trim(hiscall),">",rpt(nrxrpt)
diff --git a/lib/msk40spd.f90 b/lib/msk40spd.f90
index 9a9e108f7..4dfef05e4 100644
--- a/lib/msk40spd.f90
+++ b/lib/msk40spd.f90
@@ -125,7 +125,7 @@ subroutine msk40spd(cbig,n,ntol,mycall,hiscall,nsuccess,msgreceived,fc,fret,tret
   do ip=1,MAXCAND ! Find candidates
     iloc=maxloc(detmet(1:nstep))
     il=iloc(1)
-    if( (detmet(il) .lt. 3.0) ) exit 
+    if( (detmet(il) .lt. 3.5) ) exit 
     if( abs(detfer(il)) .le. ntol ) then 
       ndet=ndet+1
       nstart(ndet)=1+(il-1)*60+1
@@ -179,10 +179,10 @@ subroutine msk40spd(cbig,n,ntol,mycall,hiscall,nsuccess,msgreceived,fc,fret,tret
           call msk40decodeframe(ct,mycall,hiscall,xsnr,msgreceived,ndecodesuccess)
 
           if( ndecodesuccess .gt. 0 ) then
+!write(*,*) icand, iav, ipk, is, tret, fret, msgreceived
             tret=(nstart(icand)+NSPM/2)/fs
             fret=fest
             navg=sum(navmask)
-!write(*,*) icand, iav, ipk, is, tret, fret, msgreceived
             nsuccess=1
             return
           endif