WSJT-X/libm65/spec9.f90
Joe Taylor 019eb5c9ca Working toward decode capability.
git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@2628 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
2012-10-02 18:08:44 +00:00

143 lines
3.1 KiB
Fortran

subroutine spec9(c0,npts8,nsps,f0a,lagpk,fpk)
parameter (MAXFFT=31500)
complex c0(0:npts8-1)
real s(0:MAXFFT-1)
real ssym(0:9,184)
complex c(0:MAXFFT-1)
integer*1 softbit(207)
integer ibit(207)
integer*1 t1(13) !72 bits and zero tail as 8-bit bytes
integer*4 t4(69) !Symbols from t5, values 0-7
integer*4 mettab(0:255,0:1)
integer*1 tmp(72)
character*22 msg
integer isync(85)
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/
isync=0
do i=1,16
isync(ii(i))=1
enddo
idt=-400
idf=0.
fshift=fpk-f0a + 0.1*idf
twopi=8.0*atan(1.0)
dphi=twopi*fshift/1500.0
nsps8=nsps/8
nfft=nsps8
df=1500.0/nfft
s=0.
istart=lagpk*nsps8 + idt
nsym=min((npts8-istart)/nsps8,85)
print*,f0a,lagpk,fpk,fshift,nsym
do j=0,nsym-1
ia=j*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.le.8) ssym(i,1+j)=sx
s(i)=s(i) + sx
enddo
enddo
! sync=0.
! do i=1,16
! sync=sync + ssym(0,ii(i))
! enddo
do i=0,nfft-1
freq = f0a + i*df
write(71,3001) i,i*df,freq,s(i)
3001 format(i8,3f12.3)
enddo
do j=1,nsym
write(72,3002) j,(ssym(i,j),i=0,8)
3002 format(i3,9f7.2)
enddo
m0=3
ntones=8
k=0
do j=1,nsym
! print*,j,k,nsym
if(isync(j).eq.1) cycle
do m=m0-1,0,-1 !Get bit-wise soft symbols
n=2**m
r1=0.
r2=0.
do ig=0,ntones-1
! i=igray(ig,-1)
i=ig
if(iand(i,n).ne.0) then
r1=max(r1,ssym(i+1,j))
else
r2=max(r2,ssym(i+1,j))
endif
enddo
k=k+1
softbit(k)=min(127,max(-127,nint(10.0*(r1-r2)))) + 128
enddo
enddo
ibit=0
do i=1,207
if(softbit(i).lt.0) ibit(i)=1
enddo
print*,ibit
! Get the metric table
bias=0.37 !To be optimized, in decoder program
scale=10 ! ... ditto ...
open(19,file='met8.21',status='old')
do i=0,255
read(19,*) x00,x0,x1
mettab(i,0)=nint(scale*(x0-bias))
mettab(i,1)=nint(scale*(x1-bias)) !### Check range, etc. ###
enddo
close(19)
nbits=72
ndelta=17
limit=1000
print*,softbit
call fano232(softbit,nbits+31,mettab,ndelta,limit,t1,ncycles,metric,ierr, &
maxmetric,maxnp)
print*,ncycles
nbytes=(nbits+7)/8
do i=1,nbytes
n=t1(i)
t4(i)=iand(n,255)
enddo
call unpackbits(t4,nbytes,8,tmp)
call packbits(tmp,12,6,t4)
do i=1,12
if(t4(i).lt.128) t1(i)=t4(i)
if(t4(i).ge.128) t1(i)=t4(i)-256
enddo
do i=1,12
t4(i)=t1(i)
enddo
call unpackmsg(t4,msg) !Unpack decoded msg
print*,msg
return
end subroutine spec9