WSJT-X/lib/jtmsk_decode144.f90

120 lines
3.8 KiB
Fortran
Raw Normal View History

subroutine jtmsk_decode(id2,narg,line)
! Calls the experimental decoder for JTMSK 72ms ldpc messages
parameter (NMAX=30*12000)
parameter (NFFTMAX=512*1024)
parameter (NSPM=864) !Samples per JTMSK long message
integer*2 id2(0:NMAX) !Raw i*2 data, up to T/R = 30 s
integer hist(0:32868)
real d(0:NMAX) !Raw r*4 data
real ty(NMAX/512) !Ping times
real yellow(NMAX/512)
complex c(NFFTMAX) !Complex (analytic) data
complex cdat(24000) !Short segments, up to 2 s
complex cdat2(24000)
integer narg(0:14) !Arguments passed from calling pgm
character*22 msg,msg0 !Decoded message
character*80 line(100) !Decodes passed back to caller
equivalence (hist,d)
! Parameters from GUI are in narg():
nutc=narg(0) !UTC
npts=min(narg(1),NMAX) !Number of samples in id2 (12000 Hz)
newdat=narg(3) !1==> new data, compute symbol spectra
minsync=narg(4) !Lower sync limit
npick=narg(5)
t0=0.001*narg(6)
t1=0.001*narg(7)
maxlines=narg(8) !Max # of decodes to return to caller
nmode=narg(9)
nrxfreq=narg(10) !Target Rx audio frequency (Hz)
ntol=narg(11) !Search range, +/- ntol (Hz)
nhashcalls=narg(12)
naggressive=narg(14)
nsnr0=-99
nline=0
line(1:100)(1:1)=char(0)
msg0=' '
msg=msg0
hist=0
do i=0,npts-1
n=abs(id2(i))
hist(n)=hist(n)+1
enddo
ns=0
do n=0,32768
ns=ns+hist(n)
if(ns.gt.npts/2) exit
enddo
fac=1.0/(1.5*n)
d(0:npts-1)=fac*id2(0:npts-1)
! rms=sqrt(dot_product(d(0:npts-1),d(0:npts-1))/npts)
!### Would it be better to set median rms to 1.0 ?
! d(0:npts-1)=d(0:npts-1)/rms !Normalize so that rms=1.0
call mskdt(d,npts,ty,yellow,nyel)
! do i=1,nyel
! print*,i,ty(i),yellow(i)
! enddo
nyel=min(nyel,5)
n=log(float(npts))/log(2.0) + 1.0
nfft=min(2**n,1024*1024)
call analytic(d,npts,nfft,c) !Convert to analytic signal and filter
nafter=NSPM
! Process ping list (sorted by S/N) from top down.
! do n=1,nyel
do n=1,nyel
ia=ty(n)*12000.0 - NSPM/2
if(ia.lt.1) ia=1
ib=ia + 2*nafter-1
if(ib.gt.NFFTMAX) ib=NFFTMAX
iz=ib-ia+1
cdat2(1:iz)=c(ia:ib) !Select nlen complex samples
write(*,*) ty(1),ia,ib,iz
ja=ia/NSPM + 1
jb=ib/NSPM
t0=ia/12000.0
! do itry=1,21
do itry=1,1
idf1=(itry/2) * 50
if(mod(itry,2).eq.1) idf1=-idf1
if(abs(idf1).gt.ntol) exit
fpk=idf1 + nrxfreq
call tweak1(cdat2,iz,1500.0-fpk,cdat)
call syncmsk144(cdat,iz,jpk,ipk,idf,rmax,snr,metric,msg,freq)
if(metric.eq.-9999) cycle !No output if no significant sync
if(msg(1:1).eq.' ') call jtmsk_short(cdat,iz,narg,tbest,idfpk,msg)
if(msg(1:1).eq.'<' .and. naggressive.eq.0 .and. &
narg(13)/8.ne.narg(12)) msg=' '
if(msg(1:1).ne.' ') then
if(msg.ne.msg0) then
nline=nline+1
nsnr0=-99
endif
t0=(ia+jpk)/12000.0
y=10.0**(0.1*(yellow(n)-1.5))
nsnr=max(-5,nint(db(y)))
if(nsnr.gt.nsnr0 .and. nline.gt.0) then
write(line(nline),1020) nutc,nsnr,t0,nint(freq),msg
1020 format(i6.6,i4,f5.1,i5,' & ',a22)
nsnr0=nsnr
go to 900
endif
msg0=msg
if(nline.ge.maxlines) go to 900
endif
enddo
! print*,'c',nutc,n,nint(yellow(n)-4.0),freq,freq2
enddo
900 continue
! print*,'d',nutc,n,nint(yellow(n)-4.0),freq,freq2
if(line(1)(1:6).eq.' ') line(1)(1:1)=char(0)
return
end subroutine jtmsk_decode