WSJT-X/lib/fsk4hf/ft8sim.f90
Joe Taylor 76d1169140 FT8 now uses nsps=1920.
git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@7784 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
2017-07-06 13:38:06 +00:00

99 lines
3.2 KiB
Fortran

program ft8sim
! Generate simulated data for a 15-second HF/6m mode using 8-FSK.
! Output is saved to a *.wav file.
use wavhdr
include 'ft8_params.f90' !Set various constants
type(hdr) h !Header for .wav file
character arg*12,fname*17
character msg*22,msgsent*22
complex c0(0:NMAX-1)
complex c(0:NMAX-1)
integer itone(NN)
integer*2 iwave(NMAX) !Generated full-length waveform
! Get command-line argument(s)
nargs=iargc()
if(nargs.ne.6) then
print*,'Usage: ft8sim "message" DT fdop del nfiles snr'
print*,'Example: ft8sim "K1ABC W9XYZ EN37" 0.0 0.1 1.0 10 -18'
go to 999
endif
call getarg(1,msg) !Message to be transmitted
call getarg(2,arg)
read(arg,*) xdt !Time offset from nominal (s)
call getarg(3,arg)
read(arg,*) fspread !Watterson frequency spread (Hz)
call getarg(4,arg)
read(arg,*) delay !Watterson delay (ms)
call getarg(5,arg)
read(arg,*) nfiles !Number of files
call getarg(6,arg)
read(arg,*) snrdb !SNR_2500
twopi=8.0*atan(1.0)
fs=12000.0 !Sample rate (Hz)
dt=1.0/fs !Sample interval (s)
tt=NSPS*dt !Duration of symbols (s)
baud=1.0/tt !Keying rate (baud)
bw=8*baud !Occupied bandwidth (Hz)
txt=NZ*dt !Transmission length (s)
bandwidth_ratio=2500.0/(fs/2.0)
sig=sqrt(2*bandwidth_ratio) * 10.0**(0.05*snrdb)
if(snrdb.gt.90.0) sig=1.0
txt=NN*NSPS/12000.0
call genft8(msg,msgsent,itone) !Source-encode, then get itone()
write(*,1000) f0,xdt,txt,snrdb,bw,msgsent
1000 format('f0:',f9.3,' DT:',f6.2,' TxT:',f6.1,' SNR:',f6.1, &
' BW:',f4.1,2x,a22)
! call sgran()
c=0.
do ifile=1,nfiles
c0=0.
do isig=1,25
f0=(isig+2)*100.0
phi=0.0
k=-1 + nint(xdt+0.5/dt)
do j=1,NN !Generate complex waveform
dphi=twopi*(f0+itone(j)*baud)*dt
if(k.eq.0) phi=-dphi
do i=1,NSPS
k=k+1
phi=phi+dphi
if(phi.gt.twopi) phi=phi-twopi
xphi=phi
if(k.ge.0 .and. k.lt.NMAX) c0(k)=cmplx(cos(xphi),sin(xphi))
enddo
enddo
if(fspread.ne.0.0 .or. delay.ne.0.0) call watterson(c,NMAX,fs,delay,fspread)
c=c+c0
enddo
c=c*sig
if(snrdb.lt.90) then
do i=0,NMAX-1 !Add gaussian noise at specified SNR
xnoise=gran()
ynoise=gran()
c(i)=c(i) + cmplx(xnoise,ynoise)
enddo
endif
fac=32767.0
rms=100.0
if(snrdb.ge.90.0) iwave(1:NMAX)=nint(fac*real(c))
if(snrdb.lt.90.0) iwave(1:NMAX)=nint(rms*real(c))
h=default_header(12000,NMAX)
write(fname,1102) ifile
1102 format('000000_',i6.6,'.wav')
open(10,file=fname,status='unknown',access='stream')
write(10) h,iwave !Save to *.wav file
close(10)
write(*,1110) ifile,xdt,f0,snrdb,fname
1110 format(i4,f7.2,f8.2,f7.1,2x,a17)
enddo
999 end program ft8sim