WSJT-X/libm65/genjt9.f90

103 lines
3.0 KiB
Fortran

subroutine genjt9(message,minutes,msgsent,d6)
! Encodes a "JT9-minutes" message and returns array d6(85) of tone
! values in the range 0-8.
character*22 message !Message to be generated
character*22 msgsent !Message as it will be received
integer*4 mettab(0:255,0:1)
integer*4 d0(13) !72-bit message as 6-bit words
integer*1 d1(13) !72 bits and zero tail as 8-bit bytes
integer*1 d2(206) !Encoded information-carrying bits
integer*1 d3(206) !Bits from d2, after interleaving
integer*4 d4(69) !Symbols from d3, values 0-7
integer*4 d5(69) !Gray-coded symbols, values 0-7
integer*4 d6(85) !Channel symbols including sync, values 0-8
integer*4 t0(13) !72-bit message as 6-bit words
integer*1 t1(13) !72 bits and zero tail as 8-bit bytes
integer*1 t2(206) !Encoded information-carrying bits
integer*1 t3(206) !Bits from d2, after interleaving
integer*4 t4(69) !Symbols from d3, values 0-7
integer*4 t5(69) !Gray-coded symbols, values 0-7
integer*4 t6(85) !Channel symbols including sync, values 0-8
integer*1 tmp(72)
integer isync(85)
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/
data twopi/6.283185307179586476d0/
save
call packmsg(message,d0) !Pack message into 12 6-bit bytes
call unpackmsg(d0,msgsent)
call entail(d0,d1)
nsym2=206
call encode232(d1,nsym2,d2) !Convolutional code, K=32, r=1/2
call interleave9(d2,1,d3)
call packbits(d3,nsym2,3,d4)
call graycode(d4,69,1,d5)
! Insert sync symbols (ntone=0) and add 1 to the data-tone numbers.
j=0
do i=1,85
if(isync(i).eq.1) then
d6(i)=0
else
j=j+1
d6(i)=d5(j)+1
endif
enddo
if(j.ne.999) return
t6=d6
j=0
do i=1,85
if(isync(i).eq.1) cycle
j=j+1
t5(j)=t6(i)-1
enddo
call graycode(t5,69,-1,t4)
call unpackbits(t4,nsym2,3,t3)
call interleave9(t3,-1,t2)
! print*,'A',d2-t2
! Get the metric table
bias=0.37
scale=10 !Optimize?
open(19,file='met8.21',status='old')
do i=0,255
read(19,*) xjunk,x0,x1
mettab(i,0)=nint(scale*(x0-bias))
mettab(i,1)=nint(scale*(x1-bias)) !### Check range, etc. ###
enddo
print*,'b'
ndelta=17
ntimeout=0
limit=1000
call fano232(t2,72+31,mettab,ndelta,limit,t1,ncycles,metric,ierr)
print*,t1
! if(ncycles/(72+31).ge.limit) ntimeout=1
! nbytes=(nbits+7)/8
! do i=1,nbytes
! n=t1(i)
! t4(i)=iand(n,255)
! enddo
! call unpackbits(t1,9,8,tmp)
! call packbits(tmp,12,6,t0)
! print*,'z',t0
return
end subroutine genjt9