WSJT-X/lib/msk144_decode.f90

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subroutine msk144_decode(id2,npts,nutc,nprint,pchk_file,mycall,hiscall, &
bShMsgs,ntol,t0,line)
! Calls the experimental decoder for MSK 72ms/16ms messages
parameter (NMAX=30*12000)
parameter (NFFTMAX=512*1024)
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
complex c(NFFTMAX) !Complex (analytic) data
character*80 line(100) !Decodes passed back to caller
character*512 pchk_file
character*6 mycall,hiscall
logical*1 bShMsgs
line(1:100)(1:1)=char(0)
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)
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
call detectmsk144(c,npts,pchk_file,line,nline,nutc,ntol,t0)
if( nprint .ne. 0 ) then
do i=1,nline
write(*,'(a80)') line(i)
enddo
endif
if(nline.eq.0 .and. bShMsgs) then
call detectmsk32(c,npts,mycall,hiscall,line,nline,nutc,ntol,t0)
if( nprint .ne. 0 ) then
do i=1,nline
write(*,'(a80)') line(i)
enddo
endif
endif
if(line(1)(1:6).eq.' ') line(1)(1:1)=char(0)
return
end subroutine msk144_decode