mirror of https://github.com/saitohirga/WSJT-X.git
113 lines
3.0 KiB
Fortran
113 lines
3.0 KiB
Fortran
subroutine decoder(ntrSeconds,ndepth,nRxLog,c0)
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! Decoder for JT9. Can run stand-alone, reading data from *.wav files;
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! or as the back end of wsjt-x, with data placed in a shared memory region.
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! NB: For unknown reason, ***MUST*** be compiled by g95 with -O0 !!!
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parameter (NMAX=1800*12000) !Total sample intervals per 30 minutes
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parameter (NDMAX=1800*1500) !Sample intervals at 1500 Hz rate
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parameter (NSMAX=22000) !Max length of saved spectra
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character*22 msg
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character*33 line
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real*4 ccfred(NSMAX)
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integer*1 i1SoftSymbols(207)
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integer*2 id2
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complex c0(NDMAX)
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common/jt9com/ss(184,NSMAX),savg(NSMAX),id2(NMAX),nutc,ndiskdat, &
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ntr,nfqso,nagain,newdat,npts8,nfb,ntol,kin,nsynced,ndecoded
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logical first
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data first/.true./
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save
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ntrMinutes=ntrSeconds/60
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newdat=1
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nsynced=0
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ndecoded=0
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limit=1000
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if(ndepth.ge.2) limit=20000
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if(ndepth.ge.3) limit=100000
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nsps=0
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if(ntrMinutes.eq.1) then
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nsps=6912
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df3=1500.0/2048.0
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else if(ntrMinutes.eq.2) then
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nsps=15360
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df3=1500.0/2048.0
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else if(ntrMinutes.eq.5) then
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nsps=40960
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df3=1500.0/6144.0
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else if(ntrMinutes.eq.10) then
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nsps=82944
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df3=1500.0/12288.0
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else if(ntrMinutes.eq.30) then
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nsps=252000
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df3=1500.0/32768.0
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endif
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if(nsps.eq.0) stop 'Error: bad TRperiod' !Better: return an error code###
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! Now do the decoding
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kstep=nsps/2
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tstep=kstep/12000.0
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! Get sync, approx freq
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call sync9(ss,tstep,df3,ntol,nfqso,ccfred,ia,ib,ipk)
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open(13,file='decoded.txt',status='unknown')
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rewind 13
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if(first) then
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open(14,file='wsjtx_rx.log',status='unknown',position='append')
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first=.false.
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endif
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if(iand(nRxLog,2).ne.0) rewind 14
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if(iand(nRxLog,1).ne.0) then
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! Write date and time to lu 14
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endif
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fgood=0.
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df8=1500.0/(nsps/8)
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sbest=0.
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do i=ia,ib
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f=(i-1)*df3
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if((i.eq.ipk .or. ccfred(i).ge.3.0) .and. f.gt.fgood+10.0*df8) then
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call spec9(c0,npts8,nsps,f,fpk,xdt,i1SoftSymbols)
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call decode9(i1SoftSymbols,limit,nlim,msg)
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snr=10.0*log10(ccfred(i)) - 10.0*log10(2500.0/df3) + 2.0
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sync=ccfred(i) - 2.0
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if(sync.lt.0.0) sync=0.0
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nsync=sync
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if(nsync.gt.10) nsync=10
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nsnr=nint(snr)
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width=0.0
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if(ccfred(i).gt.sbest .and. fgood.eq.0.0) then
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sbest=ccfred(i)
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write(line,1010) nutc,nsync,nsnr,xdt,1000.0+fpk,width
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if(nsync.gt.0) nsynced=1
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endif
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if(msg.ne.' ') then
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write(13,1010) nutc,nsync,nsnr,xdt,1000.0+fpk,width,msg
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1010 format(i4.4,i4,i5,f6.1,f8.2,f6.2,3x,a22)
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write(14,1010) nutc,nsync,nsnr,xdt,1000.0+fpk,width,msg
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fgood=f
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nsynced=1
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ndecoded=1
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endif
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endif
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enddo
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if(fgood.eq.0.0) then
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write(13,1020) line
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write(14,1020) line
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1020 format(a33)
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endif
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call flush(13)
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call flush(14)
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close(13)
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return
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end subroutine decoder
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