mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2024-09-09 06:46:39 -04:00
git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6730 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
84 lines
2.3 KiB
Fortran
84 lines
2.3 KiB
Fortran
subroutine msk144_decode(id2,npts,nutc,nprint,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)
|
|
character*22 msg,msg0 !Decoded message
|
|
character*80 line(100) !Decodes passed back to caller
|
|
equivalence (hist,d)
|
|
|
|
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)
|
|
|
|
nyel=min(nyel,100)
|
|
|
|
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=2*NSPM
|
|
nbefore=NSPM
|
|
! Process ping list (sorted by S/N) from top down.
|
|
do n=1,nyel
|
|
ia=ty(n)*12000.0 - nbefore
|
|
if(ia.lt.1) ia=1
|
|
ib=ia + nbefore + nafter - 1
|
|
if(ib.gt.NFFTMAX) ib=NFFTMAX
|
|
iz=ib-ia+1
|
|
cdat2(1:iz)=c(ia:ib) !Select nlen complex samples
|
|
t0=ia/12000.0
|
|
call syncmsk144(cdat2,iz,msg,freq)
|
|
if(msg(1:1).ne.' ') then
|
|
! if(msg.ne.msg0) then
|
|
nline=nline+1
|
|
nsnr0=-99
|
|
! endif
|
|
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
|
|
if(nprint.ne.0) write(*,1020) nutc,nsnr,t0,nint(freq),msg
|
|
1020 format(i6.6,i4,f5.1,i5,' & ',a22)
|
|
nsnr0=nsnr
|
|
! go to 900
|
|
! endif
|
|
msg0=msg
|
|
endif
|
|
enddo
|
|
|
|
900 continue
|
|
|
|
return
|
|
end subroutine msk144_decode
|