subroutine decode9(i1SoftSymbols,limit,nlim,msg) ! Decoder for JT9 ! Input: i1SoftSymbols(207) - Single-bit soft symbols ! Output: msg - decoded message (blank if erasure) 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(0:255) logical first integer*4 mettab(0:255,0:1) data first/.true./ data xx0/ & 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/ save if(first) then ! Get the metric table ! bias=0.37 !To be optimized, in decoder program bias=0.5 scale=10 ! ... ditto ... do i=0,255 mettab(i,0)=nint(scale*(xx0(i)-bias)) if(i.ge.1) mettab(256-i,1)=mettab(i,0) enddo first=.false. endif msg=' ' nbits=72 ndelta=17 call fano232(i1SoftSymbols,nbits+31,mettab,ndelta,limit,i1DecodedBytes, & ncycles,metric,ierr) nlim=ncycles/(nbits+31) if(ncycles.lt.(nbits*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 decode9