WSJT-X/lib/jt9_decode.f90

173 lines
4.9 KiB
Fortran
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module jt9_decode
type :: jt9_decoder
procedure(jt9_decode_callback), pointer :: callback
contains
procedure :: decode
end type jt9_decoder
abstract interface
subroutine jt9_decode_callback (this, utc, sync, snr, dt, freq, drift, &
decoded)
import jt9_decoder
implicit none
class(jt9_decoder), intent(inout) :: this
integer, intent(in) :: utc
real, intent(in) :: sync
integer, intent(in) :: snr
real, intent(in) :: dt
real, intent(in) :: freq
integer, intent(in) :: drift
character(len=22), intent(in) :: decoded
end subroutine jt9_decode_callback
end interface
contains
subroutine decode(this,callback,ss,id2,nutc,nfqso,newdat,npts8,nfa, &
nfsplit,nfb,ntol,nzhsym,nagain,ndepth,nmode,nsubmode,nexp_decode)
use timer_module, only: timer
include 'constants.f90'
class(jt9_decoder), intent(inout) :: this
procedure(jt9_decode_callback) :: callback
real ss(184,NSMAX)
logical, intent(in) :: newdat, nagain
character*22 msg
real*4 ccfred(NSMAX)
real*4 red2(NSMAX)
logical ccfok(NSMAX)
logical done(NSMAX)
integer*2 id2(NTMAX*12000)
integer*1 i1SoftSymbols(207)
common/decstats/ntry65a,ntry65b,n65a,n65b,num9,numfano
save ccfred,red2
this%callback => callback
if(nmode.eq.9 .and. nsubmode.ge.1) then
call decode9w(nutc,nfqso,ntol,nsubmode,ss,id2,sync,nsnr,xdt,freq,msg)
if (associated(this%callback)) then
ndrift=0
call this%callback(nutc,sync,nsnr,xdt,freq,ndrift,msg)
end if
go to 999
endif
nsynced=0
ndecoded=0
nsps=6912 !Params for JT9-1
df3=1500.0/2048.0
tstep=0.5*nsps/12000.0 !Half-symbol step (seconds)
done=.false.
nf0=0
nf1=nfa
if(nmode.eq.65+9) nf1=nfsplit
ia=max(1,nint((nf1-nf0)/df3))
ib=min(NSMAX,nint((nfb-nf0)/df3))
lag1=-int(2.5/tstep + 0.9999)
lag2=int(5.0/tstep + 0.9999)
if(newdat) then
call timer('sync9 ',0)
call sync9(ss,nzhsym,lag1,lag2,ia,ib,ccfred,red2,ipk)
call timer('sync9 ',1)
endif
nsps8=nsps/8
df8=1500.0/nsps8
dblim=db(864.0/nsps8) - 26.2
ia1=1 !quel compiler gripe
ib1=1 !quel compiler gripe
do nqd=1,0,-1
limit=5000
ccflim=3.0
red2lim=1.6
schklim=2.2
if(iand(ndepth,7).eq.2) then
limit=10000
ccflim=2.7
endif
if(iand(ndepth,7).eq.3 .or. nqd.eq.1) then
limit=30000
ccflim=2.5
schklim=2.0
endif
if(nagain) then
limit=100000
ccflim=2.4
schklim=1.8
endif
ccfok=.false.
if(nqd.eq.1) then
nfa1=nfqso-ntol
nfb1=nfqso+ntol
ia=max(1,nint((nfa1-nf0)/df3))
ib=min(NSMAX,nint((nfb1-nf0)/df3))
ccfok(ia:ib)=(ccfred(ia:ib).gt.(ccflim-2.0)) .and. &
(red2(ia:ib).gt.(red2lim-1.0))
ia1=ia
ib1=ib
else
nfa1=nf1
nfb1=nfb
ia=max(1,nint((nfa1-nf0)/df3))
ib=min(NSMAX,nint((nfb1-nf0)/df3))
do i=ia,ib
ccfok(i)=ccfred(i).gt.ccflim .and. red2(i).gt.red2lim
enddo
ccfok(ia1:ib1)=.false.
endif
fgood=0.
do i=ia,ib
if(done(i) .or. (.not.ccfok(i))) cycle
f=(i-1)*df3
if(nqd.eq.1 .or. &
(ccfred(i).ge.ccflim .and. abs(f-fgood).gt.10.0*df8)) then
call timer('softsym ',0)
fpk=nf0 + df3*(i-1)
call softsym(id2,npts8,nsps8,newdat,fpk,syncpk,snrdb,xdt, &
freq,drift,a3,schk,i1SoftSymbols)
call timer('softsym ',1)
sync=(syncpk+1)/4.0
if(nqd.eq.1 .and. ((sync.lt.0.5) .or. (schk.lt.1.0))) cycle
if(nqd.ne.1 .and. ((sync.lt.1.0) .or. (schk.lt.1.5))) cycle
call timer('jt9fano ',0)
call jt9fano(i1SoftSymbols,limit,nlim,msg)
call timer('jt9fano ',1)
if(sync.lt.0.0 .or. snrdb.lt.dblim-2.0) sync=0.0
nsync=int(sync)
if(nsync.gt.10) nsync=10
nsnr=nint(snrdb)
ndrift=nint(drift/df3)
num9=num9+1
if(msg.ne.' ') then
numfano=numfano+1
if (associated(this%callback)) then
call this%callback(nutc,sync,nsnr,xdt,freq,ndrift,msg)
end if
iaa=max(1,i-1)
ibb=min(NSMAX,i+22)
fgood=f
nsynced=1
ndecoded=1
ccfok(iaa:ibb)=.false.
done(iaa:ibb)=.true.
endif
endif
enddo
if(nagain) exit
enddo
999 return
end subroutine decode
end module jt9_decode