subroutine extract(s3,nadd,ncount,nhist,decoded,ltext,nbmkv) real s3(64,63) character decoded*22 integer era(51),dat4(12),indx(64) integer mrsym(63),mr2sym(63),mrprob(63),mr2prob(63) logical nokv,ltext data nokv/.false./,nsec1/0/ save nbmkv=0 nfail=0 1 continue call demod64a(s3,nadd,mrsym,mrprob,mr2sym,mr2prob,ntest,nlow) if(ntest.lt.50 .or. nlow.gt.20) then ncount=-999 !Flag bad data go to 900 endif call chkhist(mrsym,nhist,ipk) if(nhist.ge.20) then nfail=nfail+1 call pctile(s3,4032,50,base) ! ### or, use ave from demod64a do j=1,63 s3(ipk,j)=base enddo if(nfail.gt.30) then decoded=' ' ncount=-1 go to 900 endif go to 1 endif call graycode65(mrsym,63,-1) call interleave63(mrsym,-1) call interleave63(mrprob,-1) ! Decode using Berlekamp-Massey algorithm nemax=30 !Max BM erasures call indexx(63,mrprob,indx) do i=1,nemax j=indx(i) if(mrprob(j).gt.120) then ne2=i-1 go to 2 endif era(i)=j-1 enddo ne2=nemax 2 decoded=' ' do nerase=0,ne2,2 call rs_decode(mrsym,era,nerase,dat4,ncount) if(ncount.ge.0) then call unpackmsg(dat4,decoded) if(iand(dat4(10),8).ne.0) ltext=.true. nbmkv=1 go to 900 endif enddo ! Berlekamp-Massey algorithm failed, try Koetter-Vardy if(nokv) go to 900 maxe=8 !Max KV errors in 12 most reliable symbols ! xlambda=12.0 xlambda=7.99 call graycode65(mr2sym,63,-1) call interleave63(mr2sym,-1) call interleave63(mr2prob,-1) nsec1=nsec1+1 write(22,rec=1) nsec1,xlambda,maxe,200,mrsym,mrprob,mr2sym,mr2prob call flush(22) call timer('kvasd ',0) #ifdef UNIX iret=system('./kvasd -q > dev_null') #else iret=system('kvasd -q > dev_null') #endif call timer('kvasd ',1) if(iret.ne.0) then if(.not.nokv) write(*,1000) 1000 format('Error in KV decoder, or no KV decoder present.') nokv=.true. go to 900 endif read(22,rec=2,err=900) nsec2,ncount,dat4 j=nsec2 !Silence compiler warning decoded=' ' ltext=.false. if(ncount.ge.0) then call unpackmsg(dat4,decoded) !Unpack the user message if(iand(dat4(10),8).ne.0) ltext=.true. nbmkv=2 endif 900 continue return end subroutine extract