WSJT-X/libm65/gen65.f90

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subroutine gen65(message,mode65,samfac,nsendingsh,msgsent,iwave,nwave)
! Encodes a JT65 message into a wavefile.
! Executes in 17 ms on opti-745.
parameter (NMAX=60*11025) !Max length of wave file
character*22 message !Message to be generated
character*22 msgsent !Message as it will be received
character*3 cok !' ' or 'OOO'
real*8 dt,phi,f,f0,dfgen,dphi,twopi,samfac
integer*2 iwave(NMAX) !Generated wave file
integer dgen(12)
integer sent(63)
logical first
integer nprc(126)
real pr(126)
data nprc/1,0,0,1,1,0,0,0,1,1,1,1,1,1,0,1,0,1,0,0, &
0,1,0,1,1,0,0,1,0,0,0,1,1,1,0,0,1,1,1,1, &
0,1,1,0,1,1,1,1,0,0,0,1,1,0,1,0,1,0,1,1, &
0,0,1,1,0,1,0,1,0,1,0,0,1,0,0,0,0,0,0,1, &
1,0,0,0,0,0,0,0,1,1,0,1,0,0,1,0,1,1,0,1, &
0,1,0,1,0,0,1,1,0,0,1,0,0,1,0,0,0,0,1,1, &
1,1,1,1,1,1/
data twopi/6.283185307179586476d0/,first/.true./
save
if(first) then
do i=1,126
pr(i)=2*nprc(i)-1
enddo
first=.false.
endif
call chkmsg(message,cok,nspecial,flip)
if(nspecial.eq.0) then
call packmsg(message,dgen) !Pack message into 72 bits
nsendingsh=0
if(iand(dgen(10),8).ne.0) nsendingsh=-1 !Plain text flag
call rs_encode(dgen,sent)
call interleave63(sent,1) !Apply interleaving
call graycode(sent,63,1) !Apply Gray code
nsym=126 !Symbols per transmission
nsps=4096
else
nsym=32
nsps=16384
nsendingsh=1 !Flag for shorthand message
endif
if(mode65.eq.0) go to 900
! Set up necessary constants
dt=1.d0/(samfac*11025.d0)
f0=118*11025.d0/1024
dfgen=mode65*11025.d0/4096.d0
phi=0.d0
i=0
k=0
do j=1,nsym
f=f0
if(nspecial.ne.0 .and. mod(j,2).eq.0) f=f0+10*nspecial*dfgen
if(nspecial.eq.0 .and. flip*pr(j).lt.0.0) then
k=k+1
f=f0+(sent(k)+2)*dfgen
endif
dphi=twopi*dt*f
do ii=1,nsps
phi=phi+dphi
if(phi.gt.twopi) phi=phi-twopi
xphi=phi
i=i+1
iwave(i)=32767.0*sin(xphi)
enddo
enddo
iwave(nsym*nsps+1:)=0
nwave=nsym*nsps + 5512
call unpackmsg(dgen,msgsent)
if(flip.lt.0.0) then
do i=22,1,-1
if(msgsent(i:i).ne.' ') goto 10
enddo
10 msgsent=msgsent(1:i)//' OOO'
endif
if(nsendingsh.eq.1) then
if(nspecial.eq.2) msgsent='RO'
if(nspecial.eq.3) msgsent='RRR'
if(nspecial.eq.4) msgsent='73'
endif
900 return
end subroutine gen65