mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2024-09-12 08:16:39 -04:00
decoder at the new frequency. CTRL-click (or CTRL-double-click) sets both Rx and Tx freqs. 2. Amplitude at end of transmission is ramped down to prevent a "key click". git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@3139 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
158 lines
4.2 KiB
Fortran
158 lines
4.2 KiB
Fortran
subroutine decoder(ss,c0)
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! Decoder for JT9.
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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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real ss(184,NSMAX)
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character*22 msg
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character*33 line
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character*80 fmt
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character*20 datetime
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real*4 ccfred(NSMAX)
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logical ccfok(NSMAX)
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integer*1 i1SoftSymbols(207)
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integer*2 id2
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integer ii(1)
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complex c0(NDMAX)
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complex c1(NDMAX)
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common/npar/nutc,ndiskdat,ntrperiod,nfqso,newdat,npts8,nfa,nfb,ntol, &
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kin,nzhsym,nsave,nagain,ndepth,nrxlog,nfsample,datetime
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common/tracer/limtrace,lu
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save
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call timer('decoder ',0)
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open(13,file='decoded.txt',status='unknown')
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ntrMinutes=ntrperiod/60
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newdat=1
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nsynced=0
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ndecoded=0
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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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fmt='(i4.4,i4,i5,f6.1,f8.0,i4,3x,a22)'
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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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fmt='(i4.4,i4,i5,f6.1,f8.1,i4,3x,a22)'
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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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fmt='(i4.4,i4,i5,f6.1,f8.1,i4,3x,a22)'
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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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fmt='(i4.4,i4,i5,f6.1,f8.2,i4,3x,a22)'
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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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fmt='(i4.4,i4,i5,f6.1,f8.2,i4,3x,a22)'
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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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kstep=nsps/2
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tstep=kstep/12000.0
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idf=ntol/df3 + 0.999
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do nqd=1,0,-1
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limit=5000
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ccflim=4.0
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if(ndepth.ge.2) then
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limit=50000
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ccflim=3.0
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endif
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if(ndepth.ge.3 .or. nqd.eq.1) then
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limit=200000
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ccflim=2.5
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endif
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if(nqd.eq.1) then
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nfa1=nfqso-ntol
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nfb1=nfqso+ntol
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else
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nfa1=nfa
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nfb1=nfb
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endif
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call timer('sync9 ',0)
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! Compute ccfred()
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call sync9(ss,nzhsym,tstep,df3,nfa1,nfb1,ntol,nfqso,ccfred,ia,ib,ipk)
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call timer('sync9 ',1)
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ccfok=.false.
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ccfok(max(ipk-idf,1):min(ipk+idf,NSMAX))=.true.
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if(nqd.eq.1) then
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ia1=ia
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ib1=ib
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else
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do i=ia+9,ib-25
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t1=ccfred(i)/(sum(ccfred(i-8:i-6)/3.0))
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t2=ccfred(i)/(sum(ccfred(i+23:i+25)/3.0))
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if(t1.ge.ccflim .and. t2.ge.ccflim) ccfok(i)=.true.
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enddo
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ccfok(ia1:ib1)=.false.
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endif
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nRxLog=0
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fgood=0.
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nsps8=nsps/8
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df8=1500.0/nsps8
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sbest=-1.0
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dblim=db(864.0/nsps8) - 26.2
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i1=max(nint((nfqso-1000)/df3 - 10),ia)
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i2=min(nint((nfqso-1000)/df3 + 10),ib)
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ii=maxloc(ccfred(i1:i2))
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i00=ii(1) + i1 - 1
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do i=ia,ib
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f=(i-1)*df3
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if(.not.ccfok(i)) cycle
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if(nqd.eq.1 .or. &
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(ccfred(i).ge.3.0 .and. abs(f-fgood).gt.10.0*df8)) then
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call timer('decode9a',0)
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fpk=1000.0 + df3*(i-1)
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c1(1:npts8)=conjg(c0(1:npts8))
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call decode9a(c1,npts8,nsps8,fpk,syncpk,snrdb,xdt,freq,drift, &
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i1SoftSymbols)
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call timer('decode9a',1)
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call timer('decode9 ',0)
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call decode9(i1SoftSymbols,limit,nlim,msg)
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call timer('decode9 ',1)
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sync=(syncpk+1)/4.0
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if(sync.lt.0.0 .or. snrdb.lt.dblim-2.0) 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(snrdb)
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ndrift=nint(drift/df3)
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if(msg.ne.' ') then
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write(*,fmt) nutc,nsync,nsnr,xdt,freq,ndrift,msg
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write(13,fmt) nutc,nsync,nsnr,xdt,freq,ndrift,msg
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fgood=f
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nsynced=1
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ndecoded=1
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ccfok(max(ia,i-3):min(ib,i+11))=.false.
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call flush(6)
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endif
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endif
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enddo
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call flush(6)
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if(nagain.ne.0) exit
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enddo
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write(*,1010) nsynced,ndecoded
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1010 format('<DecodeFinished>',2i4)
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call flush(6)
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close(13)
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call timer('decoder ',1)
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if(nstandalone.eq.0) call timer('decoder ',101)
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return
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end subroutine decoder
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