mirror of https://github.com/saitohirga/WSJT-X.git
93 lines
4.0 KiB
Fortran
93 lines
4.0 KiB
Fortran
subroutine jt9fano(i1SoftSymbols,limit,nlim,msg)
|
|
|
|
! Decoder for JT9
|
|
! Input: i1SoftSymbols(207) - Single-bit soft symbols
|
|
! Output: msg - decoded message (blank if erasure)
|
|
|
|
use packjt
|
|
character*22 msg
|
|
integer*4 i4DecodedBytes(9)
|
|
integer*4 i4Decoded6BitWords(12)
|
|
integer*1 i1DecodedBytes(13) !72 bits and zero tail as 8-bit bytes
|
|
integer*1 i1SoftSymbols(207)
|
|
integer*1 i1DecodedBits(72)
|
|
|
|
real*4 xx0(0:262)
|
|
|
|
logical first
|
|
integer*4 mettab(-128:127,0:1)
|
|
data first/.true./
|
|
data xx0/ & !Metric table
|
|
1.000, 1.000, 1.000, 1.000, 1.000, 1.000, 1.000, 1.000, &
|
|
1.000, 1.000, 1.000, 1.000, 1.000, 1.000, 1.000, 1.000, &
|
|
1.000, 1.000, 1.000, 1.000, 1.000, 1.000, 1.000, 1.000, &
|
|
1.000, 1.000, 1.000, 1.000, 1.000, 1.000, 1.000, 1.000, &
|
|
1.000, 1.000, 1.000, 1.000, 1.000, 1.000, 1.000, 1.000, &
|
|
1.000, 1.000, 1.000, 1.000, 1.000, 1.000, 1.000, 1.000, &
|
|
0.988, 1.000, 0.991, 0.993, 1.000, 0.995, 1.000, 0.991, &
|
|
1.000, 0.991, 0.992, 0.991, 0.990, 0.990, 0.992, 0.996, &
|
|
0.990, 0.994, 0.993, 0.991, 0.992, 0.989, 0.991, 0.987, &
|
|
0.985, 0.989, 0.984, 0.983, 0.979, 0.977, 0.971, 0.975, &
|
|
0.974, 0.970, 0.970, 0.970, 0.967, 0.962, 0.960, 0.957, &
|
|
0.956, 0.953, 0.942, 0.946, 0.937, 0.933, 0.929, 0.920, &
|
|
0.917, 0.911, 0.903, 0.895, 0.884, 0.877, 0.869, 0.858, &
|
|
0.846, 0.834, 0.821, 0.806, 0.790, 0.775, 0.755, 0.737, &
|
|
0.713, 0.691, 0.667, 0.640, 0.612, 0.581, 0.548, 0.510, &
|
|
0.472, 0.425, 0.378, 0.328, 0.274, 0.212, 0.146, 0.075, &
|
|
0.000,-0.079,-0.163,-0.249,-0.338,-0.425,-0.514,-0.606, &
|
|
-0.706,-0.796,-0.895,-0.987,-1.084,-1.181,-1.280,-1.376, &
|
|
-1.473,-1.587,-1.678,-1.790,-1.882,-1.992,-2.096,-2.201, &
|
|
-2.301,-2.411,-2.531,-2.608,-2.690,-2.829,-2.939,-3.058, &
|
|
-3.164,-3.212,-3.377,-3.463,-3.550,-3.768,-3.677,-3.975, &
|
|
-4.062,-4.098,-4.186,-4.261,-4.472,-4.621,-4.623,-4.608, &
|
|
-4.822,-4.870,-4.652,-4.954,-5.108,-5.377,-5.544,-5.995, &
|
|
-5.632,-5.826,-6.304,-6.002,-6.559,-6.369,-6.658,-7.016, &
|
|
-6.184,-7.332,-6.534,-6.152,-6.113,-6.288,-6.426,-6.313, &
|
|
-9.966,-6.371,-9.966,-7.055,-9.966,-6.629,-6.313,-9.966, &
|
|
-5.858,-9.966,-9.966,-9.966,-9.966,-9.966,-9.966,-9.966, &
|
|
-9.966,-9.966,-9.966,-9.966,-9.966,-9.966,-9.966,-9.966, &
|
|
-9.966,-9.966,-9.966,-9.966,-9.966,-9.966,-9.966,-9.966, &
|
|
-9.966,-9.966,-9.966,-9.966,-9.966,-9.966,-9.966,-9.966, &
|
|
-9.966,-9.966,-9.966,-9.966,-9.966,-9.966,-9.966,-9.966, &
|
|
-9.966,-9.966,-9.966,-9.966,-9.966,-9.966,-9.966,-9.966, &
|
|
1.43370769e-019,2.64031087e-006,6.25548654e+028, &
|
|
2.44565251e+020,4.74227538e+030,10497312.,7.74079654e-039/
|
|
save
|
|
|
|
if(first) then
|
|
! Get the metric table
|
|
bias=0.5
|
|
scale=50
|
|
ndelta=nint(3.4*scale)
|
|
ib=160 !Break point
|
|
slope=2 !Slope beyond break
|
|
do i=0,255
|
|
mettab(i-128,0)=nint(scale*(xx0(i)-bias))
|
|
if(i.gt.ib) mettab(i-128,0)=mettab(ib-128,0) - slope*(i-ib)
|
|
if(i.ge.1) mettab(128-i,1)=mettab(i-128,0)
|
|
enddo
|
|
mettab(-128,1)=mettab(-127,1)
|
|
first=.false.
|
|
endif
|
|
|
|
msg=' '
|
|
nbits=72
|
|
call fano232(i1SoftSymbols,nbits+31,mettab,ndelta,limit,i1DecodedBytes, &
|
|
ncycles,metric,ierr)
|
|
|
|
nlim=ncycles/(nbits+31)
|
|
if(ncycles.lt.((nbits+31)*limit)) then
|
|
nbytes=(nbits+7)/8
|
|
do i=1,nbytes
|
|
n=i1DecodedBytes(i)
|
|
i4DecodedBytes(i)=iand(n,255)
|
|
enddo
|
|
call unpackbits(i4DecodedBytes,nbytes,8,i1DecodedBits)
|
|
call packbits(i1DecodedBits,12,6,i4Decoded6BitWords)
|
|
call unpackmsg(i4Decoded6BitWords,msg) !Unpack decoded msg
|
|
if(index(msg,'000AAA ').gt.0) msg=' '
|
|
endif
|
|
|
|
return
|
|
end subroutine jt9fano
|