subroutine extract(s3,nadd,nqd,ntrials,naggressive,ndepth,nexp_decode, & ncount,nhist,decoded,ltext,nsf) ! Input: ! s3 64-point spectra for each of 63 data symbols ! nadd number of spectra summed into s3 ! nqd 0/1 to indicate decode attempt at QSO frequency ! Output: ! ncount number of symbols requiring correction (-1 for no KV decode) ! nhist maximum number of identical symbol values ! decoded decoded message (if ncount >=0) ! ltext true if decoded message is free text ! nsf 0=no decode; 1=BM decode; 2=KV decode use prog_args !shm_key, exe_dir, data_dir use packjt real s3(64,63) character decoded*22 integer dat4(12) integer mrsym(63),mr2sym(63),mrprob(63),mr2prob(63) integer correct(63),tmp(63) integer param(0:7) integer indx(0:62) real*8 tt logical nokv,ltext common/chansyms65/correct data nokv/.false./,nsec1/0/ save nbirdie=20 npct=50 afac1=1.1 nsf=0 nfail=0 decoded=' ' call pctile(s3,4032,npct,base) s3=s3/base ! Get most reliable and second-most-reliable symbol values, and their ! probabilities 1 call demod64a(s3,nadd,afac1,mrsym,mrprob,mr2sym,mr2prob,ntest,nlow) call chkhist(mrsym,nhist,ipk) !Test for birdies and QRM if(nhist.ge.nbirdie) then nfail=nfail+1 call pctile(s3,4032,npct,base) s3(ipk,1:63)=base if(nfail.gt.30) then decoded=' ' ncount=-1 go to 900 endif go to 1 endif call graycode65(mrsym,63,-1) !Remove gray code call interleave63(mrsym,-1) !Remove interleaving call interleave63(mrprob,-1) call graycode65(mr2sym,63,-1) !Remove gray code and interleaving call interleave63(mr2sym,-1) !from second-most-reliable symbols call interleave63(mr2prob,-1) ntry=0 nverbose=0 call timer('sfrsd ',0) call sfrsd2(mrsym,mrprob,mr2sym,mr2prob,ntrials,nverbose,correct, & param,indx,tt,ntry) call timer('sfrsd ',1) ncandidates=param(0) nhard=param(1) nsoft=param(2) nerased=param(3) if(nhard.lt.0 .and. ndepth.ge.5) then call timer('exp_deco',0) call exp_decode65(mrsym,mrprob,mr2sym,nexp_decode,nhard,nsoft,nbest, & correct) if(nbest.gt.72+2*naggressive) then nhard=-1 endif call timer('exp_deco',1) endif ndone=ndone+1 ncount=-1 decoded=' ' ltext=.false. if(nhard.ge.0) then !turn the corrected symbol array into channel symbols for subtraction !pass it back to jt65a via common block "chansyms65" do i=1,12 dat4(i)=correct(13-i) enddo do i=1,63 tmp(i)=correct(64-i) enddo correct(1:63)=tmp(1:63) call interleave63(correct,63,1) call graycode65(correct,63,1) call unpackmsg(dat4,decoded) !Unpack the user message ! open(43,file='stats.dat',access='append',status='unknown') ! write(43,*) nhard,nsoft,nerased,ntry ! close(43) ncount=0 if(iand(dat4(10),8).ne.0) ltext=.true. nsf=1 endif 900 continue return end subroutine extract