program wsprcode
! This program provides examples of the source encoding, convolutional
! error-control coding, bit and symbol ordering, and synchronizing
! information contained in WSPR messages.
parameter (NSYM=162)
parameter (MAXSYM=176)
character*22 msg,msg2
integer*1 data0(7)
integer*1 data1(7)
integer*1 dat(NSYM)
integer*1 softsym(NSYM)
! Define the sync vector:
integer*1 sync(NSYM)
data sync/ &
1,1,0,0,0,0,0,0,1,0,0,0,1,1,1,0,0,0,1,0, &
0,1,0,1,1,1,1,0,0,0,0,0,0,0,1,0,0,1,0,1, &
0,0,0,0,0,0,1,0,1,1,0,0,1,1,0,1,0,0,0,1, &
1,0,1,0,0,0,0,1,1,0,1,0,1,0,1,0,1,0,0,1, &
0,0,1,0,1,1,0,0,0,1,1,0,1,0,1,0,0,0,1,0, &
0,0,0,0,1,0,0,1,0,0,1,1,1,0,1,1,0,0,1,1, &
0,1,0,0,0,1,1,1,0,0,0,0,0,1,0,1,0,0,1,1, &
0,0,0,0,0,0,0,1,1,0,1,0,1,1,0,0,0,1,1,0, &
0,0/
! Metric table for decoding from soft symbols
integer mettab(0:255,0:1)
data mettab/ &
5, 5, 5, 5, 5, 5, 5, 5, 5, 5, &
5, 5, 5, 5, 5, 5, 5, 5, 5, 5, &
5, 5, 5, 5, 5, 5, 5, 5, 5, 5, &
5, 5, 5, 5, 5, 5, 5, 5, 5, 5, &
5, 5, 5, 5, 5, 5, 5, 5, 5, 5, &
5, 5, 5, 5, 5, 5, 5, 5, 5, 5, &
5, 5, 5, 5, 5, 5, 5, 5, 5, 5, &
5, 5, 5, 5, 5, 5, 5, 5, 5, 4, &
4, 4, 4, 4, 4, 4, 4, 4, 4, 4, &
4, 4, 4, 4, 4, 4, 4, 4, 4, 4, &
3, 3, 3, 3, 3, 3, 3, 3, 3, 2, &
2, 2, 2, 2, 1, 1, 1, 1, 0, 0, &
-1, -1, -1, -2, -2, -3, -4, -4, -5, -6, &
-7, -7, -8, -9, -10, -11, -12, -12, -13, -14, &
-15, -16, -17, -17, -18, -19, -20, -21, -22, -22, &
-23, -24, -25, -26, -26, -27, -28, -29, -30, -30, &
-31, -32, -33, -33, -34, -35, -36, -36, -37, -38, &
-38, -39, -40, -41, -41, -42, -43, -43, -44, -45, &
-45, -46, -47, -47, -48, -49, -49, -50, -51, -51, &
-52, -53, -53, -54, -54, -55, -56, -56, -57, -57, &
-58, -59, -59, -60, -60, -61, -62, -62, -62, -63, &
-64, -64, -65, -65, -66, -67, -67, -67, -68, -69, &
-69, -70, -70, -71, -72, -72, -72, -72, -73, -74, &
-75, -75, -75, -77, -76, -76, -78, -78, -80, -81, &
-80, -79, -83, -82, -81, -82, -82, -83, -84, -84, &
-84, -87, -86, -87, -88, -89, -89, -89, -88, -87, &
-86, -87, -84, -84, -84, -83, -82, -82, -81, -82, &
-83, -79, -80, -81, -80, -78, -78, -76, -76, -77, &
-75, -75, -75, -74, -73, -72, -72, -72, -72, -71, &
-70, -70, -69, -69, -68, -67, -67, -67, -66, -65, &
-65, -64, -64, -63, -62, -62, -62, -61, -60, -60, &
-59, -59, -58, -57, -57, -56, -56, -55, -54, -54, &
-53, -53, -52, -51, -51, -50, -49, -49, -48, -47, &
-47, -46, -45, -45, -44, -43, -43, -42, -41, -41, &
-40, -39, -38, -38, -37, -36, -36, -35, -34, -33, &
-33, -32, -31, -30, -30, -29, -28, -27, -26, -26, &
-25, -24, -23, -22, -22, -21, -20, -19, -18, -17, &
-17, -16, -15, -14, -13, -12, -12, -11, -10, -9, &
-8, -7, -7, -6, -5, -4, -4, -3, -2, -2, &
-1, -1, -1, 0, 0, 1, 1, 1, 1, 2, &
2, 2, 2, 2, 3, 3, 3, 3, 3, 3, &
3, 3, 3, 4, 4, 4, 4, 4, 4, 4, &
4, 4, 4, 4, 4, 4, 4, 4, 4, 4, &
4, 4, 4, 4, 5, 5, 5, 5, 5, 5, &
5, 5, 5, 5, 5, 5, 5, 5, 5, 5, &
5, 5, 5, 5, 5, 5, 5, 5, 5, 5, &
5, 5, 5, 5, 5, 5, 5, 5, 5, 5, &
5, 5, 5, 5, 5, 5, 5, 5, 5, 5, &
5, 5, 5, 5, 5, 5, 5, 5, 5, 5, &
5, 5, 5, 5, 5, 5, 5, 5, 5, 5, &
5, 5, 5, 5, 5, 5, 5, 5, 5, 5, &
5, 5/
! Get command-line argument(s)
nargs=iargc()
if(nargs.ne.1) then
print*,'Usage: WSPRcode "message"'
go to 999
endif
call getarg(1,msg) !Get message from command line
write(*,1000) msg
1000 format('Message: ',a22)
nbits=50+31 !User bits=50, constraint length=32
nbytes=(nbits+7)/8
ndelta=50
limit=20000
data0=0
call wqencode(msg,ntype0,data0) !Source encoding
write(*,1002) data0
1002 format(/'Source-encoded message (50 bits, hex):',7z3.2)
call encode232(data0,nbytes,dat,MAXSYM) !Convolutional encoding
call inter_mept(dat,1) !Interleaving
write(*,1004)
1004 format(/'Data symbols:')
write(*,1006) (dat(i),i=1,NSYM)
1006 format(5x,30i2)
write(*,1008)
1008 format(/'Sync symbols:')
write(*,1006) (sync(i),i=1,NSYM)
write(*,1010)
1010 format(/'Channel symbols:')
write(*,1006) (2*dat(i)+sync(i),i=1,NSYM)
call inter_mept(dat,-1) !Remove interleaving
softsym=-dat !Simulate soft symbols
! Call the sequential (Fano algorithm) decoder
call fano232(softsym,nbits,mettab,ndelta,limit,data1,ncycles,metric,nerr)
call wqdecode(data1,msg2,ntype1)
write(*,1020) ntype1
1020 format(/'Message type: ',i7)
write(*,1030) msg2
1030 format('Decoded message: ',a22)
999 end program wsprcode