WSJT-X/lib/jtmsk_decode.f90
Bill Somerville ae031aad83 Allow for, and add where necessary, a second character after mode
The decoded message processing relies on fixed column positions so the
extra character used in message  averaging to indicate sync flips must
also be allowed for in other modes.  This is done by inserting a space
character.

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6681 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
2016-05-17 19:35:38 +00:00

120 lines
3.9 KiB
Fortran

subroutine jtmsk_decode(id2,narg,line)
! Decoder for JTMSK mode
parameter (NMAX=30*12000)
parameter (NFFTMAX=512*1024)
parameter (NSPM=1404) !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)
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
nbefore=NSPM
nafter=4*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 + nafter
if(ib.gt.NFFTMAX) ib=NFFTMAX
iz=ib-ia+1
cdat2(1:iz)=c(ia:ib) !Select nlen complex samples
ja=ia/NSPM + 1
jb=ib/NSPM
t0=ia/12000.0
do itry=1,21
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 syncmsk(cdat,iz,jpk,ipk,idf,rmax,snr,metric,msg)
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
freq=fpk+idf
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
call rectify_msk(cdat2(jpk:jpk+NSPM-1),msg,narg(13),freq2)
freq=freq2
if(msg(1:1).eq.'<') freq=freq2+idfpk
!### Check freq values !!!
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