WSJT-X/lib/geniscat.f90
Bill Somerville 97704efba8 Reintegrate merge from wsjtx_exp branch.
git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6122 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
2015-11-18 01:28:12 +00:00

56 lines
1.5 KiB
Fortran

subroutine geniscat(msg,msgsent,itone)
! Generate an ISCAT waveform.
parameter (NSZ=1291)
character msg*28,msgsent*28 !Message to be transmitted
integer imsg(30)
integer itone(NSZ)
real*8 sps
character c*42
integer icos(4) !Costas array
data icos/0,1,3,2/
data nsync/4/,nlen/2/,ndat/18/
data c/'0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ /.?@-'/
sps=256.d0*12000.d0/11025.d0
nsym=int(30*12000.d0/sps)
nblk=nsync+nlen+ndat
do i=22,1,-1
if(msg(i:i).ne.' ' .and. msg(i:i).ne.char(0)) exit
enddo
nmsg=i
msglen=nmsg+1
k=0
kk=1
imsg(1)=40 !Always start with BOM char: '@'
do i=1,nmsg !Define the tone sequence
imsg(i+1)=36 !Illegal char set to blank
do j=1,42
if(msg(i:i).eq.c(j:j)) imsg(i+1)=j-1
enddo
enddo
do i=1,nsym !Total symbols in 30 s
j=mod(i-1,nblk)+1
if(j.le.nsync) then
itone(i)=icos(j) !Insert 4x4 Costas array
else if(j.gt.nsync .and. j.le.nsync+nlen) then
itone(i)=msglen !Insert message-length indicator
if(j.ge.nsync+2) then
n=msglen + 5*(j-nsync-1)
if(n.gt.41) n=n-42
itone(i)=n
endif
else
k=k+1
kk=mod(k-1,msglen)+1
itone(i)=imsg(kk)
endif
enddo
msgsent=msg
return
end subroutine geniscat