Further improvements to JT9 decoder.

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@4993 ab8295b8-cf94-4d9e-aec4-7959e3be5d79

lib/afc9.f90

@@ -6,9 +6,9 @@ subroutine afc9(c3,npts,fsample,a,syncpk)
   a(1)=0.                                   !f0
   a(2)=0.                                   !f1
   a(3)=0.                                   !f2
-  deltaa(1)=0.2
-  deltaa(2)=0.01
-  deltaa(3)=0.01
+  deltaa(1)=0.4
+  deltaa(2)=0.1
+  deltaa(3)=0.1
   nterms=3
 
 ! Start the iteration
@@ -42,17 +42,17 @@ subroutine afc9(c3,npts,fsample,a,syncpk)
         delta=delta*(1./(1.+(chisq1-chisq2)/(chisq3-chisq2))+0.5)
         a(j)=a(j)-delta
         deltaa(j)=deltaa(j)*fn/3.
-!        write(*,4000) iter,j,a,deltaa,-chisq2
-!4000    format(i1,i2,6f10.4,f9.3)
+!        write(*,4000) iter,j,a,-chisq2
+!4000    format(i1,i2,3f10.4,f11.3)
      enddo
      chisqr=fchisq(c3,npts,fsample,a)
-     if(chisqr/chisqr0.gt.0.9999) exit
+     if(chisqr/chisqr0.gt.0.99) exit
      chisqr0=chisqr
   enddo
 
   syncpk=-chisqr
-!  write(*,4001) a,deltaa,-chisq2
-!4001 format(3x,6f10.4,f9.3)
+!  write(*,4001) a,-chisq2
+!4001 format(3x,3f10.4,f11.3)
 
   return
 end subroutine afc9

lib/chkss2.f90

@@ -2,22 +2,18 @@ subroutine chkss2(ss2,freq,drift,schk)
 
   real ss2(0:8,85)
   real s(0:8,85)
-  real s1(0:5)
   include 'jt9sync.f90'
 
   ave=sum(ss2)/(9*85)
   if(freq+drift.eq.-999999.0) ave=0.      !To silence compiler warning
   s=ss2/ave-1.0
 
-!  call zplot9(s,freq,drift)
   s1=0.
-  do lag=0,5
-     do i=1,16
-        j=ii(i)+lag
-        if(j.le.85) s1(lag)=s1(lag) + s(0,j)
-     enddo
+  do i=1,16
+     j=ii(i)
+     if(j.le.85) s1=s1 + s(0,j)
   enddo
-  schk=s1(0)/16.0
+  schk=s1/16.0
 
   return
 end subroutine chkss2

lib/decjt9.f90

@@ -94,9 +94,10 @@ subroutine decjt9(ss,id2,nutc,nfqso,newdat,npts8,nfa,nfsplit,nfb,ntol,  &
            call timer('softsym ',1)
 
            sync=(syncpk+1)/4.0
-           if(maxval(i1SoftSymbols).eq.0) cycle
-           if(nqd.eq.1 .and. ((sync.lt.0.5) .or. (schk.lt.2.0))) cycle
-           if(nqd.ne.1 .and. ((sync.lt.1.0) .or. (schk.lt.schklim))) cycle
+!           if(maxval(i1SoftSymbols).eq.0) cycle
+!           if(nqd.eq.1 .and. ((sync.lt.0.5) .or. (schk.lt.1.0))) cycle
+!           if(nqd.ne.1 .and. ((sync.lt.1.0) .or. (schk.lt.1.5))) cycle
+           if(nqd.ne.1 .and. ((sync.lt.1.0) .or. (schk.lt.1.8))) cycle
 
            call timer('jt9fano ',0)
            call jt9fano(i1SoftSymbols,limit,nlim,msg)

lib/fchisq.f90

@@ -34,7 +34,7 @@ real function fchisq(c3,npts,fsample,a)
         sum0=sum0+pp
      endif
   enddo
-  sync=(sum1/16.0)/(sum0/69.0) - 1.0
+  sync=sum1/10000.0
   fchisq=-sync
 
   return

lib/jt9fano.f90

@@ -69,7 +69,7 @@ subroutine jt9fano(i1SoftSymbols,limit,nlim,msg)
        ncycles,metric,ierr)
 
   nlim=ncycles/(nbits+31)
-  if(ncycles.lt.(nbits*limit)) then
+  if(ncycles.lt.((nbits+31)*limit)) then
      nbytes=(nbits+7)/8
      do i=1,nbytes
         n=i1DecodedBytes(i)

lib/symspec2.f90

@@ -34,10 +34,6 @@ subroutine symspec2(c5,nz3,nsps8,nspsd,fsample,freq,drift,snrdb,schk,    &
   enddo
 
   call chkss2(ss2,freq,drift,schk)
-  if(schk.lt.1.8) then
-     i1SoftSymbolsScrambled=0
-     go to 900
-  endif
 
   ss=0.
   sig=0.
@@ -87,5 +83,5 @@ subroutine symspec2(c5,nz3,nsps8,nspsd,fsample,freq,drift,snrdb,schk,    &
      enddo
   enddo
 
-900 return
+  return
 end subroutine symspec2