subroutine decoder(ss,c0) ! Decoder for JT9. parameter (NMAX=1800*12000) !Total sample intervals per 30 minutes parameter (NDMAX=1800*1500) !Sample intervals at 1500 Hz rate parameter (NSMAX=22000) !Max length of saved spectra real ss(184,NSMAX) character*22 msg character*33 line character*80 fmt character*20 datetime real*4 ccfred(NSMAX) logical ccfok(NSMAX) integer*1 i1SoftSymbols(207) integer*2 id2 integer ii(1) complex c0(NDMAX) complex c1(NDMAX) common/npar/nutc,ndiskdat,ntrperiod,nfqso,newdat,npts8,nfa,nfb,ntol, & kin,nzhsym,nsave,nagain,ndepth,nrxlog,nfsample,datetime common/tracer/limtrace,lu save call timer('decoder ',0) open(13,file='decoded.txt',status='unknown') ntrMinutes=ntrperiod/60 newdat=1 nsynced=0 ndecoded=0 nsps=0 if(ntrMinutes.eq.1) then nsps=6912 df3=1500.0/2048.0 fmt='(i4.4,i4,i5,f6.1,f8.0,i4,3x,a22)' else if(ntrMinutes.eq.2) then nsps=15360 df3=1500.0/2048.0 fmt='(i4.4,i4,i5,f6.1,f8.1,i4,3x,a22)' else if(ntrMinutes.eq.5) then nsps=40960 df3=1500.0/6144.0 fmt='(i4.4,i4,i5,f6.1,f8.1,i4,3x,a22)' else if(ntrMinutes.eq.10) then nsps=82944 df3=1500.0/12288.0 fmt='(i4.4,i4,i5,f6.1,f8.2,i4,3x,a22)' else if(ntrMinutes.eq.30) then nsps=252000 df3=1500.0/32768.0 fmt='(i4.4,i4,i5,f6.1,f8.2,i4,3x,a22)' endif if(nsps.eq.0) stop 'Error: bad TRperiod' !Better: return an error code### kstep=nsps/2 tstep=kstep/12000.0 idf=ntol/df3 + 0.999 do nqd=1,0,-1 limit=5000 ccflim=4.0 if(ndepth.ge.2) then limit=50000 ccflim=3.0 endif if(ndepth.ge.3 .or. nqd.eq.1) then limit=200000 ccflim=2.5 endif if(nqd.eq.1) then nfa1=nfqso-ntol nfb1=nfqso+ntol else nfa1=nfa nfb1=nfb endif call timer('sync9 ',0) ! Compute ccfred() call sync9(ss,nzhsym,tstep,df3,nfa1,nfb1,ntol,nfqso,ccfred,ia,ib,ipk) call timer('sync9 ',1) ccfok=.false. ccfok(max(ipk-idf,1):min(ipk+idf,NSMAX))=.true. if(nqd.eq.1) then ia1=ia ib1=ib else do i=ia+9,ib-25 t1=ccfred(i)/(sum(ccfred(i-8:i-6)/3.0)) t2=ccfred(i)/(sum(ccfred(i+23:i+25)/3.0)) if(t1.ge.ccflim .and. t2.ge.ccflim) ccfok(i)=.true. enddo ccfok(ia1:ib1)=.false. endif nRxLog=0 fgood=0. nsps8=nsps/8 df8=1500.0/nsps8 sbest=-1.0 dblim=db(864.0/nsps8) - 26.2 i1=max(nint((nfqso-1000)/df3 - 10),ia) i2=min(nint((nfqso-1000)/df3 + 10),ib) ii=maxloc(ccfred(i1:i2)) i00=ii(1) + i1 - 1 do i=ia,ib f=(i-1)*df3 if(.not.ccfok(i)) cycle if(nqd.eq.1 .or. & (ccfred(i).ge.3.0 .and. abs(f-fgood).gt.10.0*df8)) then call timer('decode9a',0) fpk=1000.0 + df3*(i-1) c1(1:npts8)=conjg(c0(1:npts8)) call decode9a(c1,npts8,nsps8,fpk,syncpk,snrdb,xdt,freq,drift, & i1SoftSymbols) call timer('decode9a',1) call timer('decode9 ',0) call decode9(i1SoftSymbols,limit,nlim,msg) call timer('decode9 ',1) sync=(syncpk+1)/4.0 if(sync.lt.0.0 .or. snrdb.lt.dblim-2.0) sync=0.0 nsync=sync if(nsync.gt.10) nsync=10 nsnr=nint(snrdb) ndrift=nint(drift/df3) if(msg.ne.' ') then write(*,fmt) nutc,nsync,nsnr,xdt,freq,ndrift,msg write(13,fmt) nutc,nsync,nsnr,xdt,freq,ndrift,msg fgood=f nsynced=1 ndecoded=1 ccfok(max(ia,i-3):min(ib,i+11))=.false. call flush(6) endif endif enddo call flush(6) if(nagain.ne.0) exit enddo write(*,1010) nsynced,ndecoded 1010 format('',2i4) call flush(6) close(13) call timer('decoder ',1) if(nstandalone.eq.0) call timer('decoder ',101) return end subroutine decoder