subroutine decoder(ntrSeconds,nRxLog,c0) ! Decoder for JT9. Can run stand-alone, reading data from *.wav files; ! or as the back end of wsjt-x, with data placed in a shared memory region. ! NB: For unknown reason, ***MUST*** be compiled by g95 with -O0 !!! 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 character*22 msg character*33 line real*4 ccfred(NSMAX) integer*1 i1SoftSymbols(207) integer*2 id2 complex c0(NDMAX) common/jt9com/ss(184,NSMAX),savg(NSMAX),id2(NMAX),nutc,ndiskdat, & ntr,nfqso,nagain,newdat,npts8,nfb,ntol,kin logical first data first/.true./ save ntrMinutes=ntrSeconds/60 newdat=1 nsps=0 if(ntrMinutes.eq.1) then nsps=6912 df3=1500.0/2048.0 else if(ntrMinutes.eq.2) then nsps=15360 df3=1500.0/2048.0 else if(ntrMinutes.eq.5) then nsps=40960 df3=1500.0/6144.0 else if(ntrMinutes.eq.10) then nsps=82944 df3=1500.0/12288.0 else if(ntrMinutes.eq.30) then nsps=252000 df3=1500.0/32768.0 endif if(nsps.eq.0) stop 'Error: bad TRperiod' !Better: return an error code### ! Now do the decoding kstep=nsps/2 tstep=kstep/12000.0 ! Get sync, approx freq call sync9(ss,tstep,df3,ntol,nfqso,ccfred,ia,ib,ipk) open(13,file='decoded.txt',status='unknown') rewind 13 if(first) then open(14,file='wsjtx_rx.log',status='unknown',position='append') first=.false. endif if(iand(nRxLog,2).ne.0) rewind 14 if(iand(nRxLog,1).ne.0) then ! Write date and time to lu 14 endif fgood=0. df8=1500.0/(nsps/8) sbest=0. do i=ia,ib f=(i-1)*df3 if((i.eq.ipk .or. ccfred(i).ge.10.0) .and. f.gt.fgood+10.0*df8) then call spec9(c0,npts8,nsps,f,fpk,xdt,i1SoftSymbols) call decode9(i1SoftSymbols,msg) call pctile(ccfred(ia),ib-ia+1,50,xmed) snr=10.0*log10(ccfred(i)/xmed) - 10.0*log10(2500.0/df3) + 2.0 sync=ccfred(i)/xmed - 2.0 if(sync.lt.0.0) sync=0.0 nsync=sync if(nsync.gt.10) nsync=10 nsnr=nint(snr) width=0.0 if(ccfred(i).gt.sbest .and. fgood.eq.0.0) then sbest=ccfred(i) write(line,1010) nutc,nsync,nsnr,xdt,1000.0+fpk,width endif if(msg.ne.' ') then write(13,1010) nutc,nsync,nsnr,xdt,1000.0+fpk,width,msg 1010 format(i4.4,i4,i5,f6.1,f8.2,f6.2,3x,a22) write(14,1010) nutc,nsync,nsnr,xdt,1000.0+fpk,width,msg fgood=f endif endif enddo if(fgood.eq.0.0) then write(13,1020) line write(14,1020) line 1020 format(a33) endif call flush(13) call flush(14) close(13) return end subroutine decoder