259 lines
7.7 KiB
Plaintext
259 lines
7.7 KiB
Plaintext
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subroutine mskrtd(id2,nutc0,tsec,ntol,nrxfreq,ndepth,mycall,mygrid,hiscall, &
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bshmsg,bcontest,btrain,pcoeffs,bswl,datadir,line)
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! Real-time decoder for MSK144.
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! Analysis block size = NZ = 7168 samples, t_block = 0.597333 s
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! Called from hspec() at half-block increments, about 0.3 s
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parameter (NZ=7168) !Block size
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parameter (NSPM=864) !Number of samples per message frame
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parameter (NFFT1=8192) !FFT size for making analytic signal
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parameter (NPATTERNS=4) !Number of frame averaging patterns to try
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parameter (NRECENT=10) !Number of recent calls to remember
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parameter (NSHMEM=50) !Number of recent SWL messages to remember
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character*4 decsym !"&" for mskspd or "^" for long averages
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character*22 msgreceived !Decoded message
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character*22 msglast,msglastswl !Used for dupechecking
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character*80 line !Formatted line with UTC dB T Freq Msg
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character*12 mycall,hiscall
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character*6 mygrid
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character*12 recent_calls(NRECENT)
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character*22 recent_shmsgs(NSHMEM)
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character*512 datadir
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complex cdat(NFFT1) !Analytic signal
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complex c(NSPM) !Coherently averaged complex data
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complex ct(NSPM)
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integer*2 id2(NZ) !Raw 16-bit data
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integer iavmask(8)
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integer iavpatterns(8,NPATTERNS)
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integer npkloc(10)
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integer nhasharray(NRECENT,NRECENT)
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integer nsnrlast,nsnrlastswl
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real d(NFFT1)
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real pow(8)
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real softbits(144)
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real xmc(NPATTERNS)
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real*8 pcoeffs(5)
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logical*1 bshmsg,bcontest,btrain,bswl
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logical*1 first
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logical*1 bshdecode
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logical*1 seenb4
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logical*1 bflag
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logical*1 bvar
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data first/.true./
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data iavpatterns/ &
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1,1,1,1,0,0,0,0, &
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0,0,1,1,1,1,0,0, &
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1,1,1,1,1,0,0,0, &
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1,1,1,1,1,1,1,0/
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data xmc/2.0,4.5,2.5,3.5/ !Used to set time at center of averaging mask
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save first,tsec0,nutc00,pnoise,cdat,msglast,msglastswl, &
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nsnrlast,nsnrlastswl,recent_calls,nhasharray,recent_shmsgs
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if(first) then
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tsec0=tsec
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nutc00=nutc0
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pnoise=-1.0
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do i=1,nrecent
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recent_calls(i)(1:12)=' '
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enddo
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do i=1,nshmem
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recent_shmsgs(i)(1:22)=' '
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enddo
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msglast=' '
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msglastswl=' '
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nsnrlast=-99
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nsnrlastswl=-99
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first=.false.
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endif
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fc=nrxfreq
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! Dupe checking setup
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if(nutc00.ne.nutc0 .or. tsec.lt.tsec0) then ! reset dupe checker
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msglast=' '
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msglastswl=' '
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nsnrlast=-99
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nsnrlastswl=-99
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nutc00=nutc0
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endif
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tframe=float(NSPM)/12000.0
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line=char(0)
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msgreceived=' '
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max_iterations=10
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niterations=0
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d(1:NZ)=id2
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rms=sqrt(sum(d(1:NZ)*d(1:NZ))/NZ)
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if(rms.lt.1.0) go to 999
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fac=1.0/rms
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d(1:NZ)=fac*d(1:NZ)
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d(NZ+1:NFFT1)=0.
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bvar=.true.
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if( btrain ) bvar=.false. ! if training, turn off rx eq
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call analytic(d,NZ,NFFT1,cdat,pcoeffs,bvar)
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! Calculate average power for each frame and for the entire block.
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! If decode is successful, largest power will be taken as signal+noise.
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! If no decode, entire-block average will be used to update noise estimate.
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pmax=-99
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do i=1,8
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ib=(i-1)*NSPM+1
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ie=ib+NSPM-1
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pow(i)=real(dot_product(cdat(ib:ie),cdat(ib:ie)))*rms**2
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pmax=max(pmax,pow(i))
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enddo
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pavg=sum(pow)/8.0
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! Short ping decoder uses squared-signal spectrum to determine where to
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! center a 3-frame analysis window and attempts to decode each of the
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! 3 frames along with 2- and 3-frame averages.
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np=8*NSPM
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call msk144spd(cdat,np,ntol,ndecodesuccess,msgreceived,fc,fest,tdec,navg,ct, &
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softbits,recent_calls,nrecent)
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if(ndecodesuccess.eq.0 .and. (bshmsg.or.bswl)) then
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call msk40spd(cdat,np,ntol,mycall(1:6),hiscall(1:6),bswl,nhasharray, &
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recent_calls,nrecent,ndecodesuccess,msgreceived,fc,fest,tdec,navg)
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endif
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if( ndecodesuccess .ge. 1 ) then
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tdec=tsec+tdec
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ipk=0
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is=0
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goto 900
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endif
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! If short ping decoder doesn't find a decode,
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! Fast - short ping decoder only.
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! Normal - try 4-frame averages
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! Deep - try 4-, 5- and 7-frame averages.
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npat=NPATTERNS
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if( ndepth .eq. 1 ) npat=0
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if( ndepth .eq. 2 ) npat=2
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do iavg=1,npat
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iavmask=iavpatterns(1:8,iavg)
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navg=sum(iavmask)
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deltaf=10.0/real(navg) ! search increment for frequency sync
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npeaks=2
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call msk144sync(cdat(1:8*NSPM),8,ntol,deltaf,iavmask,npeaks,fc, &
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fest,npkloc,nsyncsuccess,xmax,c)
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if( nsyncsuccess .eq. 0 ) cycle
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do ipk=1,npeaks
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do is=1,3
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ic0=npkloc(ipk)
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if(is.eq.2) ic0=max(1,ic0-1)
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if(is.eq.3) ic0=min(NSPM,ic0+1)
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ct=cshift(c,ic0-1)
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call msk144decodeframe(ct,softbits,msgreceived,ndecodesuccess, &
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recent_calls,nrecent)
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if(ndecodesuccess .gt. 0) then
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tdec=tsec+xmc(iavg)*tframe
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goto 900
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endif
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enddo !Slicer dither
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enddo !Peak loop
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enddo
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msgreceived=' '
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! no decode - update noise level used for calculating displayed snr.
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if( pnoise .lt. 0 ) then ! initialize noise level
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pnoise=pavg
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elseif( pavg .gt. pnoise ) then ! noise level is slow to rise
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pnoise=0.9*pnoise+0.1*pavg
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elseif( pavg .lt. pnoise ) then ! and quick to fall
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pnoise=pavg
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endif
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go to 999
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900 continue
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! Successful decode - estimate snr
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if( pnoise .gt. 0.0 ) then
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snr0=10.0*log10(pmax/pnoise-1.0)
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else
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snr0=0.0
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endif
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nsnr=nint(snr0)
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bshdecode=.false.
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if( msgreceived(1:1) .eq. '<' ) bshdecode=.true.
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if(.not. bshdecode) then
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call msk144signalquality(ct,snr0,fest,tdec,softbits,msgreceived,hiscall, &
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btrain,datadir,ncorrected,eyeopening,pcoeffs)
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endif
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decsym=' & '
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if( btrain ) decsym=' ^ '
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if( msgreceived(1:1).eq.'<') then
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ncorrected=0
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eyeopening=0.0
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endif
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if( nsnr .lt. -8 ) nsnr=-8
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if( nsnr .gt. 24 ) nsnr=24
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! Dupe check.
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bflag=ndecodesuccess.eq.1 .and. &
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(msgreceived.ne.msglast .or. nsnr.gt.nsnrlast .or. tsec.lt.tsec0)
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if(bflag) then
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msglast=msgreceived
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nsnrlast=nsnr
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if(.not. bshdecode) then
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call update_hasharray(recent_calls,nrecent,nhasharray)
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! Should we call fix_contest_msg() only if bcontest is true?
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call fix_contest_msg(mycall(1:6),mygrid,hiscall(1:6),msgreceived)
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endif
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write(line,1020) nutc0,nsnr,tdec,nint(fest),decsym,msgreceived, &
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navg,ncorrected,eyeopening,char(0)
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1020 format(i6.6,i4,f5.1,i5,a4,a22,i2,i3,f5.1,a1)
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elseif(bswl .and. ndecodesuccess.ge.2) then
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seenb4=.false.
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do i=1,nshmem
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if( msgreceived .eq. recent_shmsgs(i) ) then
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seenb4=.true.
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endif
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enddo
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call update_recent_shmsgs(msgreceived,recent_shmsgs,nshmem)
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bflag=seenb4 .and. &
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(msgreceived.ne.msglastswl .or. nsnr.gt.nsnrlastswl .or. tsec.lt.tsec0) &
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.and. nsnr.gt.-6
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if(bflag) then
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msglastswl=msgreceived
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nsnrlastswl=nsnr
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write(line,1020) nutc0,nsnr,tdec,nint(fest),decsym,msgreceived, &
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navg,ncorrected,eyeopening,char(0)
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endif
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endif
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999 tsec0=tsec
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return
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end subroutine mskrtd
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subroutine update_recent_shmsgs(message,msgs,nsize)
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character*22 msgs(nsize)
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character*22 message
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logical*1 seen
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seen=.false.
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do i=1,nsize
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if( msgs(i) .eq. message ) seen=.true.
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enddo
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if( .not. seen ) then
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do i=nsize,2,-1
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msgs(i)=msgs(i-1)
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enddo
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msgs(1)=message
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endif
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return
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end subroutine update_recent_shmsgs
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