subroutine decode9(i1SoftSymbols,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) integer*1 i1 logical first integer*4 mettab(0:255,0:1) equivalence (i1,i4) data first/.true./ save if(first) then ! Get the metric table ! bias=0.37 !To be optimized, in decoder program bias=0.0 !Seems better, in jt9.exe ??? scale=10 ! ... ditto ... open(19,file='met8.21',status='old') do i=0,255 read(19,*) x00,x0,x1 mettab(i,0)=nint(scale*(x0-bias)) mettab(i,1)=nint(scale*(x1-bias)) !### Check range, etc. ### enddo close(19) first=.false. endif msg=' ' nbits=72 ndelta=17 limit=100000 call fano232(i1SoftSymbols,nbits+31,mettab,ndelta,limit,i1DecodedBytes, & ncycles,metric,ierr) 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 endif return end subroutine decode9