Some more work on code comparisons.

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6454 ab8295b8-cf94-4d9e-aec4-7959e3be5d79

lib/JTMSKfer.f90

@@ -33,9 +33,10 @@ program JTMSKfer
   bias=0.0
   scale=20.0
   xln2=log(2.0)
+  mettab=0
   do i=128,156
-     x0=log(max(0.0001,2.0*xp(i-127)))/xln2
+     x0=log(max(0.001,2.0*xp(i-127)))/xln2
-     x1=log(max(0.001,2.0*(1.0-xp(i-127))))/xln2
+     x1=log(max(0.001,2.0*(1-xp(i-127))))/xln2
      mettab(i,0)=nint(scale*(x0-bias))
      mettab(i,1)=nint(scale*(x1-bias))
      mettab(256-i,0)=mettab(i,1)
@@ -48,7 +49,7 @@ program JTMSKfer
      mettab(256-i,1)=mettab(i,0)
   enddo
 
-  rdscale=2.0 ! empirically optimized
+  rdscale=2.0
   ntrials=1000000
   rate=72.0/198.0
   msg="123"
@@ -67,7 +68,7 @@ program JTMSKfer
 
 !  call sgran()
 
-  do idb=0,11
+  do idb=6,11
     db=idb/2.0-0.5   ! Eb/N0=1/(2*R*sigma^2), so sigma= sqrt( 1/(2*R*Eb/N0) )
     sigma=1/sqrt( 2*rate*(10**(db/10.0)) )
 

lib/ldpc/jtmode_codes/160-80-sf4.results

@@ -1,14 +1,15 @@
 sf4 160,80 ldpc, Eb/N0_dB, ngood, nundet, 10^6 trials
--0.5 2906 0
+columns 2,3 decoder uses variable sigma, columns 4,5 decoder uses fixed sigma=0.9 
-0.0 18899 1
+-0.5 2906 0  10862 5
-0.5 78344 3
+0.0 18899 1  34663 6
-1.0 220956 9
+0.5 78344 3  94319 3
-1.5 447994 12
+1.0 220956 9 215720 9
-2.0 694624 5
+1.5 447994 12 405922 9
-2.5 876494 4
+2.0 694624 5 631688 5
-3.0 965704 1
+2.5 876494 4 825223 2
-3.5 993584 1
+3.0 965704 1 940486 1
-4.0 999160 0
+3.5 993584 1 986229 1
-4.5 999920 0
+4.0 999160 0 997916 0
-5.0 999993 0
+4.5 999920 0 999792 0
+5.0 999993 0 999982 0
 

lib/ldpc/jtmode_codes/fig_compare.gnuplot

@@ -14,7 +14,12 @@ set grid
 set logscale y
 plot [-1:6] [1e-6:1] \
    "160-80-sf4.results" using 1:(1000000-$2)/1000000 with linespoints lt 2 lw 2 pt 2, \
-   "160-80-sf4.results" using 1:($3/1000000) with linespoints lt 2 lw 2 pt 3, \
+   "160-80-sf4.results" using 1:($3/1000000) with linespoints lt 2 lw 2 pt 2, \
-   "jtmskcode.results" using 1:(100000-$2)/100000 with linespoints lt 1 lw 2 pt 7, \
+   "160-80-sf4.results" using 1:(1000000-$4)/1000000 with linespoints lt 3 lw 2 pt 4, \
+   "160-80-sf4.results" using 1:($5/1000000) with linespoints lt 2 lw 3 pt 4, \
+   "ldpc-144-72-sf2.results" using 1:(1000000-$2)/1000000 with linespoints lt 3 lw 2 pt 5, \
+   "ldpc-144-72-sf2.results" using 1:($3/1000000) with linespoints lt 3 lw 2 pt 5, \
+   "jtmskcode.results" using 1:(1000000-$4)/1000000 with linespoints lt 1 lw 2 pt 7, \
+   "jtmskcode.results" using 1:($5/1000000) with linespoints lt 1 lw 2 pt 7, \
    "compare.lab" with labels
-
+exit

lib/ldpc/jtmode_codes/jtmskcode.results

@@ -1,11 +1,12 @@
--0.50  1470  4
+rate 1/2 constraint len 13, bpsk, ngood, nbad 10^5 trials, 10^6 trials
- 0.00  4403  2
+-0.50  1470  4  
- 0.50 11167  2
+ 0.00  4403  2 43968 30
- 1.00 24082  1
+ 0.50 11167  2 111824 33
- 1.50 42779  4
+ 1.00 24082  1 238157 21
- 2.00 63417  0
+ 1.50 42779  4 425263 20
- 2.50 81290  1
+ 2.00 63417  0 634824 14
- 3.00 92388  0
+ 2.50 81290  1 812206 2
+ 3.00 92388  0 924507 2
  3.50 97560  0
  4.00 99390  0
  4.50 99864  0