WSJT-X/decode65.f

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