WSJT-X/lib/decoder.f90

187 lines
5.1 KiB
Fortran
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subroutine decoder(ss,c0,nstandalone)
! 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*80 fmt
character*20 datetime
real*4 ccfred(NSMAX)
logical ccfok(NSMAX)
logical done(NSMAX)
integer*1 i1SoftSymbols(207)
complex c0(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 system_clock(iclock0,iclock_rate,iclock_max) !###
nfreqs0=0
nfreqs1=0
ndecodes0=0
ndecodes1=0
call timer('decoder ',0)
open(13,file='decoded.txt',status='unknown')
ntrMinutes=ntrperiod/60
newdat=1
nsynced=0
ndecoded=0
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)'
else if(ntrMinutes.eq.2) then
nsps=15360
df3=1500.0/2048.0
fmt='(i4.4,i4,i5,f6.1,f8.0,i4,3x,a22)'
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)'
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)'
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)'
endif
if(nsps.eq.0) stop 'Error: bad TRperiod' !Better: return an error code###
tstep=0.5*nsps/12000.0 !Half-symbol step (seconds)
! idf=ntol/df3 + 0.999
done=.false.
do nqd=1,0,-1
limit=5000
ccflim=4.0
if(ndepth.ge.2) then
limit=50000
ccflim=3.0
endif
if(ndepth.ge.3 .or. nqd.eq.1) then
limit=200000
ccflim=2.5
endif
if(nqd.eq.1) then
nfa1=nfqso-ntol
nfb1=nfqso+ntol
else
nfa1=nfa
nfb1=nfb
endif
ia=max(1,nint((nfa1-1000)/df3))
ib=min(NSMAX,nint((nfb1-1000)/df3))
lag1=-(2.5/tstep + 0.9999)
lag2=5.0/tstep + 0.9999
call timer('sync9 ',0)
! Compute ccfred()
call sync9(ss,nzhsym,lag1,lag2,ia,ib,ccfred,ipk)
call timer('sync9 ',1)
ccfok=.false.
if(nqd.eq.1) then
ccfok(ipk)=.true.
do i=ia,ib
ccfok(i)=ccfred(i).gt.ccflim
enddo
ia1=ia
ib1=ib
else
do i=ia,ib
ccfok(i)=ccfred(i).gt.ccflim
enddo
ccfok(ia1:ib1)=.false.
endif
nRxLog=0
fgood=0.
nsps8=nsps/8
df8=1500.0/nsps8
dblim=db(864.0/nsps8) - 26.2
do i=ia,ib
f=(i-1)*df3
if(done(i) .or. (.not.ccfok(i)) .or. (ccfred(i).lt.ccflim-1.0) .or. &
(ccfred(i).lt.ccfred(i+1))) cycle
if(nqd.eq.1 .or. &
(ccfred(i).ge.ccflim .and. abs(f-fgood).gt.10.0*df8)) then
if(nqd.eq.0) nfreqs0=nfreqs0+1
if(nqd.eq.1) nfreqs1=nfreqs1+1
call timer('softsym ',0)
fpk=1000.0 + df3*(i-1)
call softsym(c0,npts8,nsps8,newdat,fpk,syncpk,snrdb,xdt,freq, &
drift,i1SoftSymbols)
call timer('softsym ',1)
call timer('decode9 ',0)
call decode9(i1SoftSymbols,limit,nlim,msg)
call timer('decode9 ',1)
sync=(syncpk+1)/4.0
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)
write(38,3002) nutc,nsnr,i,freq,ccfred(i),nlim,msg
3002 format(i4.4,i5,i6,2f8.1,i9,2x,a22)
if(msg.ne.' ') then
if(nqd.eq.0) ndecodes0=ndecodes0+1
if(nqd.eq.1) ndecodes1=ndecodes1+1
write(*,fmt) nutc,nsync,nsnr,xdt,freq,ndrift,msg
write(13,fmt) nutc,nsync,nsnr,xdt,freq,ndrift,msg
! write(14,1014) nutc,nsync,nsnr,xdt,freq,ndrift,ccfred(i),nlim,msg
!1014 format(i4.4,i4,i5,f6.1,f8.0,i4,f9.1,i9,3x,a22)
iaa=max(1,i-3)
ibb=min(NSMAX,i+11)
fgood=f
nsynced=1
ndecoded=1
ccfok(iaa:ibb)=.false.
done(iaa:ibb)=.true.
call flush(6)
endif
endif
enddo
call flush(6)
if(nagain.ne.0) exit
enddo
write(*,1010) nsynced,ndecoded
1010 format('<DecodeFinished>',2i4)
call flush(6)
close(13)
! call flush(14)
call timer('decoder ',1)
if(nstandalone.eq.0) call timer('decoder ',101)
call system_clock(iclock,iclock_rate,iclock_max)
write(39,3001) nutc,nfreqs1,nfreqs0,ndecodes1,ndecodes0+ndecodes1, &
float(iclock-iclock0)/iclock_rate
3001 format(5i8,f10.3)
call flush(38)
call flush(39)
return
end subroutine decoder