WSJT-X/map65/libm65/gen_q65_cwave.f90

53 lines
1.1 KiB
Fortran

subroutine gen_q65_cwave(msg,ntxfreq,ntone_spacing,msgsent,cwave,nwave)
! Encodes a Q65 message to yield complex cwave() at fsample = 96000 Hz
use packjt
use q65_encoding
parameter (NMAX=60*96000)
character*22 msg
character*22 msgsent !Message as it will be received
character*37 msg37
real*8 t,dt,phi,f,f0,dfgen,dphi,twopi,tsym
complex cwave(NMAX)
integer codeword(65),itone(85)
integer icos7(0:6)
data icos7/2,5,6,0,4,1,3/ !Defines a 7x7 Costas array
data twopi/6.283185307179586476d0/
save
msgsent=msg
msg37=''
msg37(1:22)=msg
call get_q65_tones(msg37,codeword,itone)
! Set up necessary constants
nsym=85
tsym=7200.d0/12000.d0
dt=1.d0/96000.d0
f0=ntxfreq
dfgen=ntone_spacing*12000.d0/7200.d0
phi=0.d0
dphi=twopi*dt*f0
i=0
nwave=85*7200*96000.d0/12000.d0
t=0.d0
j0=0
do i=1,nwave
t=t+dt
j=t/tsym + 1
if(j.gt.85) exit
if(j.ne.j0) then
f=f0 + itone(j)*dfgen
dphi=twopi*dt*f
j0=j
endif
phi=phi+dphi
if(phi.gt.twopi) phi=phi-twopi
xphi=phi
cwave(i)=cmplx(cos(xphi),-sin(xphi))
enddo
999 return
end subroutine gen_q65_cwave