WSJT-X/lib/wsprd/wspr_wav.f90
2020-11-06 09:33:44 -06:00

50 lines
1011 B
Fortran

subroutine wspr_wav(baud,xdt,h,f0,itone,snrdb,iwave)
! Generate iwave() from itone().
include 'wspr_params.f90'
integer itone(NN)
integer*2 iwave(NMAX)
real*8 twopi,dt,dphi0,dphi1,dphi,phi
real dat(NMAX)
twopi=8.d0*atan(1.d0)
dt=1.d0/12000.d0
baud=375.0/256.0
dat=0.
if(snrdb.lt.90) then
do i=1,NMAX
dat(i)=gran() !Generate gaussian noise
enddo
bandwidth_ratio=2500.0/6000.0
sig=sqrt(2*bandwidth_ratio)*10.0**(0.05*snrdb)
else
sig=1.0
endif
phi=0.d0
k=nint(xdt/dt)
do j=1,NN
dphi=twopi*(f0+h*(itone(j)-1.5)*baud)*dt
do i=1,NSPS0
k=k+1
phi=mod(phi+dphi,twopi)
if(k.gt.0 .and. k.le.NMAX) dat(k)=dat(k) + sig*sin(phi)
enddo
enddo
rms=100.0
if(snrdb.lt.90.0) then
dat=rms*dat;
if(maxval(abs(dat)).gt.32767.0) print*,"Warning - data will be clipped."
else
datpk=maxval(abs(dat))
fac=32767.9/datpk
dat=fac*dat
endif
iwave=nint(dat)
return
end subroutine wspr_wav