WSJT-X/lib/decoder.f90

142 lines
3.7 KiB
Fortran
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subroutine decoder(ss,c0)
! Decoder for JT9.
parameter (NMAX=1800*12000) !Total sample intervals per 30 minutes
parameter (NDMAX=1800*1500) !Sample intervals at 1500 Hz rate
parameter (NSMAX=22000) !Max length of saved spectra
real ss(184,NSMAX)
character*22 msg
character*33 line
character*80 fmt,fmt14
character*20 datetime
real*4 ccfred(NSMAX)
integer*1 i1SoftSymbols(207)
integer*2 id2
integer ii(1)
complex c0(NDMAX)
complex c1(NDMAX)
common/npar/nutc,ndiskdat,ntrperiod,nfqso,newdat,npts8,nfa,nfb,ntol, &
kin,nzhsym,nsave,nagain,ndepth,nrxlog,nfsample,datetime
common/tracer/limtrace,lu
save
call timer('decoder ',0)
ntrMinutes=ntrperiod/60
newdat=1
nsynced=0
ndecoded=0
limit=200
if(ndepth.ge.2) limit=2000
if(ndepth.ge.3) limit=20000
nsps=0
if(ntrMinutes.eq.1) then
nsps=6912
df3=1500.0/2048.0
fmt='(i4.4,i4,i5,f6.1,f8.0,i4,3x,a22)'
fmt14='(i4.4,i4,i5,f6.1,f8.0,i4,3x,a22,i8,i3)'
else if(ntrMinutes.eq.2) then
nsps=15360
df3=1500.0/2048.0
fmt='(i4.4,i4,i5,f6.1,f8.1,i4,3x,a22)'
fmt14='(i4.4,i4,i5,f6.1,f8.1,i4,3x,a22,i8,i3)'
else if(ntrMinutes.eq.5) then
nsps=40960
df3=1500.0/6144.0
fmt='(i4.4,i4,i5,f6.1,f8.1,i4,3x,a22)'
fmt14='(i4.4,i4,i5,f6.1,f8.1,i4,3x,a22,i8,i3)'
else if(ntrMinutes.eq.10) then
nsps=82944
df3=1500.0/12288.0
fmt='(i4.4,i4,i5,f6.1,f8.2,i4,3x,a22)'
fmt14='(i4.4,i4,i5,f6.1,f8.2,i4,3x,a22,i8,i3)'
else if(ntrMinutes.eq.30) then
nsps=252000
df3=1500.0/32768.0
fmt='(i4.4,i4,i5,f6.1,f8.2,i4,3x,a22)'
fmt14='(i4.4,i4,i5,f6.1,f8.2,i4,3x,a22,i8,i3)'
endif
if(nsps.eq.0) stop 'Error: bad TRperiod' !Better: return an error code###
kstep=nsps/2
tstep=kstep/12000.0
call timer('sync9 ',0)
call sync9(ss,nzhsym,tstep,df3,ntol,nfqso,ccfred,ia,ib,ipk) !Compute ccfred
call timer('sync9 ',1)
! open(13,file='decoded.txt',status='unknown')
! rewind 13
if(iand(nRxLog,2).ne.0) rewind 14
if(iand(nRxLog,1).ne.0) then
! Write date and time to lu 14
endif
nRxLog=0
fgood=0.
nsps8=nsps/8
df8=1500.0/nsps8
sbest=-1.0
dblim=db(864.0/nsps8) - 26.2
10 ii=maxloc(ccfred(ia:ib))
i=ii(1) + ia - 1
f=(i-1)*df3
if((i.eq.ipk .or. ccfred(i).ge.3.0) .and. abs(f-fgood).gt.10.0*df8) then
call timer('decode9a',0)
fpk=1000.0 + df3*(i-1)
c1(1:npts8)=conjg(c0(1:npts8))
call decode9a(c1,npts8,nsps8,fpk,syncpk,snrdb,xdt,freq,drift,i1SoftSymbols)
call timer('decode9a',1)
call timer('decode9 ',0)
call decode9(i1SoftSymbols,limit,nlim,msg)
call timer('decode9 ',1)
sync=(syncpk-1.0)/2.0
if(sync.lt.0.0 .or. snrdb.lt.dblim-2.0) sync=0.0
nsync=sync
if(nsync.gt.10) nsync=10
nsnr=nint(snrdb)
ndrift=nint(drift/df3)
if(sync.gt.sbest .and. fgood.eq.0.0) then
sbest=sync
write(line,fmt) nutc,nsync,nsnr,xdt,freq,ndrift
if(nsync.gt.0) nsynced=1
endif
if(msg.ne.' ') then
write(*,fmt) nutc,nsync,nsnr,xdt,freq,ndrift,msg
write(14,fmt14) nutc,nsync,nsnr,xdt,freq,ndrift,msg,nlim,ntrMinutes
fgood=f
nsynced=1
ndecoded=1
ccfred(max(ia,i-3):min(ib,i+11))=0.
endif
endif
ccfred(i)=0.
if(maxval(ccfred(ia:ib)).gt.3.0) go to 10
if(fgood.eq.0.0) then
write(*,1020) line
write(14,1020) line
1020 format(a33)
endif
write(*,1010) nsynced,ndecoded
1010 format('<DecodeFinished>',2i4)
flush(6)
call flush(6)
call flush(14)
call timer('decoder ',1)
if(nstandalone.eq.0) call timer('decoder ',101)
return
end subroutine decoder