WSJT-X/lib/spec9.f90

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subroutine spec9(c0,npts8,nsps,f0a,fpk,xdt,i1SoftSymbols)
parameter (MAXFFT=31500)
complex c0(0:npts8-1)
real ssym(0:7,69)
complex c(0:MAXFFT-1)
integer*1 i1SoftSymbolsScrambled(207)
integer*1 i1SoftSymbols(207)
integer isync(85) !Sync vector
data isync/ &
1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1,0,0,0,0, &
1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,0,0,0,1,0, &
0,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0, &
0,0,1,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0, &
1,0,0,0,1/
integer ii(16) !Locations of sync symbols
data ii/1,6,11,16,21,26,31,39,45,51,57,63,69,75,81,85/
integer ig(0:7)
data ig/0,1,3,2,7,6,4,5/ !Gray code removal
save
nsps8=nsps/8
foffset=fpk-f0a
istart=1520
call peakdf9(c0,npts8,nsps8,istart,foffset,idf)
fpk=fpk + idf*0.1*1500.0/nsps8
foffset=foffset + idf*0.1*1500.0/nsps8
call peakdt9(c0,npts8,nsps8,istart,foffset,idt)
istart=istart + 0.0625*nsps8*idt
xdt=istart/1500.0 - 1.0
! write(*,3002) 0.0625*nsps8*idt/1500.0,idf*0.1*1500.0/nsps8
!3002 format(2f8.2)
fshift=foffset
twopi=8.0*atan(1.0)
dphi=twopi*fshift/1500.0
nfft=nsps8
nsym=min((npts8-istart)/nsps8,85)
k=0
do j=1,nsym
if(isync(j).eq.1) cycle
k=k+1
ia=(j-1)*nsps8 + istart
ib=ia+nsps8-1
c(0:nfft-1)=c0(ia:ib)
phi=0.
do i=0,nfft-1
phi=phi + dphi
c(i)=c(i) * cmplx(cos(phi),-sin(phi))
enddo
call four2a(c,nfft,1,-1,1)
do i=0,nfft-1
sx=real(c(i))**2 + aimag(c(i))**2
if(i.ge.1 .and. i.le.8) ssym(ig(i-1),k)=sx
enddo
enddo
m0=3
ntones=8
k=0
do j=1,69
do m=m0-1,0,-1 !Get bit-wise soft symbols
n=2**m
r1=0.
r2=0.
do i=0,ntones-1
if(iand(i,n).ne.0) then
r1=max(r1,ssym(i,j))
else
r2=max(r2,ssym(i,j))
endif
enddo
k=k+1
i1SoftSymbolsScrambled(k)=min(127,max(-127,nint(10.0*(r1-r2)))) + 128
enddo
enddo
call interleave9(i1SoftSymbolsScrambled,-1,i1SoftSymbols)
return
end subroutine spec9