2006-09-06 14:09:05 -04:00
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subroutine decode65(dat,npts,dtx,dfx,flip,ndepth,neme,nsked,
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+ mycall,hiscall,hisgrid,mode65,nafc,decoded,ncount,
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+ deepmsg,qual)
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C Decodes JT65 data, assuming that DT and DF have already been determined.
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real dat(npts) !Raw data
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real s2(77,126)
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real s3(64,63)
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real ftrack(126)
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character decoded*22,deepmsg*22
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character mycall*12,hiscall*12,hisgrid*6
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include 'avecom.h'
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include 'prcom.h'
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save
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dt=2.0/11025.0 !Sample interval (2x downsampled data)
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istart=nint(dtx/dt) !Start index for synced FFTs
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nsym=126
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C Compute spectra of the channel symbols
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f0=1270.46 + dfx
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call spec2d65(dat,npts,nsym,flip,istart,f0,ftrack,nafc,mode65,s2)
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do j=1,63
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k=mdat(j) !Points to data symbol
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if(flip.lt.0.0) k=mdat2(j)
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do i=1,64
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s3(i,j)=s2(i+7,k)
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enddo
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enddo
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nadd=mode65
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call extract(s3,nadd,ncount,decoded) !Extract the message
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qual=0.
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if(ndepth.ge.1) call deep65(s3,mode65,neme,
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+ nsked,flip,mycall,hiscall,hisgrid,deepmsg,qual)
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if(ncount.lt.0) decoded=' '
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C Suppress "birdie messages":
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if(decoded(1:7).eq.'000AAA ') decoded=' '
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if(decoded(1:7).eq.'0L6MWK ') decoded=' '
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C Save symbol spectra for possible decoding of average.
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do j=1,63
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k=mdat(j)
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if(flip.lt.0.0) k=mdat2(j)
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call move(s2(8,k),ppsave(1,j,nsave),64)
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enddo
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return
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end
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