WSJT-X/lib/ft8/ft8sim.f90

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5.5 KiB
Fortran
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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
parameter (NWAVE=NN*NSPS)
type(hdr) h !Header for .wav file
character arg*12,fname*17
character msg*37,msgsent*37,msg0*37
complex c0(0:NMAX-1)
complex c(0:NMAX-1)
real wave(NMAX)
integer itone(NN)
integer*1 msgbits(77)
integer*2 iwave(NMAX) !Generated full-length waveform
! Get command-line argument(s)
nargs=iargc()
if(nargs.ne.8) then
print*,'Usage: ft8sim "message" nsig|f0 DT fdop del width nfiles snr'
print*,'Examples: ft8sim "K1ABC W9XYZ EN37" 1500.0 0.0 0.1 1.0 0 10 -18'
print*,' ft8sim "K1ABC W9XYZ EN37" 10 0.0 0.1 1.0 25 10 -18'
print*,' ft8sim "K1ABC W9XYZ EN37" 25 0.0 0.1 1.0 25 10 -18'
print*,' ft8sim "K1ABC RR73; W9XYZ <KH1/KH7Z> -11" 300 0 0 0 25 1 -10'
go to 999
endif
call getarg(1,msg) !Message to be transmitted
call getarg(2,arg)
read(arg,*) f0 !Frequency (only used for single-signal)
call getarg(3,arg)
read(arg,*) xdt !Time offset from nominal (s)
call getarg(4,arg)
read(arg,*) fspread !Watterson frequency spread (Hz)
call getarg(5,arg)
read(arg,*) delay !Watterson delay (ms)
call getarg(6,arg)
read(arg,*) width !Filter transition width (Hz)
call getarg(7,arg)
read(arg,*) nfiles !Number of files
call getarg(8,arg)
read(arg,*) snrdb !SNR_2500
nsig=1
if(f0.lt.100.0) then
nsig=f0
f0=1500
endif
nfiles=abs(nfiles)
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
! Source-encode, then get itone()
if(index(msg,';').le.0) then
i3bit=0
call genft8(msg,i3bit,0,1,msgsent,msgbits,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)
else
call foxgen_wrap(msg,msgbits,itone)
write(*,1001) f0,xdt,txt,snrdb,bw,msg
1001 format('f0:',f9.3,' DT:',f6.2,' TxT:',f6.1,' SNR:',f6.1, &
' BW:',f4.1,2x,a37)
endif
write(*,1030) msgbits(1:56)
1030 format(/'Call1: ',28i1,' Call2: ',28i1)
write(*,1032) msgbits(57:72),msgbits(73:75)
1032 format('Grid: ',16i1,' 3Bit: ',3i1)
write(*,1034) itone
1034 format(/'Channel symbols:'/79i1/)
call sgran()
msg0=msg
do ifile=1,nfiles
c=0.
do isig=1,nsig
c0=0.
if(nsig.eq.2) then
if(index(msg,'R-').gt.0) f0=500
i1=index(msg,' ')
msg(i1+4:i1+4)=char(ichar('A')+isig-1)
if(isig.eq.2) then
f0=f0+100
endif
call genft8(msg,i3bit,msgsent,msgbits,itone)
endif
if(nsig.eq.25) then
f0=(isig+2)*100.0
else if(nsig.eq.50) then
msg=msg0
f0=1000.0 + (isig-1)*60.0
i1=index(msg,' ')
i2=index(msg(i1+1:),' ') + i1
msg(i1+2:i1+2)=char(ichar('0')+mod(isig-1,10))
msg(i1+3:i1+3)=char(ichar('A')+mod(isig-1,26))
msg(i1+4:i1+4)=char(ichar('A')+mod(isig-1,26))
msg(i1+5:i1+5)=char(ichar('A')+mod(isig-1,26))
write(msg(i2+3:i2+4),'(i2.2)') isig-1
if(ifile.ge.2 .and. isig.eq.ifile-1) then
write(msg(i2+1:i2+4),1002) -isig
1002 format('R',i3.2)
f0=600.0 + mod(isig-1,5)*60.0
endif
call genft8(msg,i3bit,msgsent,msgbits,itone)
endif
! k=nint((xdt+0.5+0.01*gran())/dt)
k=nint((xdt+0.5)/dt)
ia=k
phi=0.0
do j=1,NN !Generate complex waveform
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dphi=twopi*(f0*dt+itone(j)/real(NSPS))
do i=1,NSPS
if(k.ge.0 .and. k.lt.NMAX) c0(k)=cmplx(cos(phi),sin(phi))
k=k+1
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phi=mod(phi+dphi,twopi)
enddo
enddo
if(fspread.ne.0.0 .or. delay.ne.0.0) call watterson(c0,NMAX,fs,delay,fspread)
c=c+sig*c0
enddo
ib=k
wave=real(c)
peak=maxval(abs(wave(ia:ib)))
rms=sqrt(dot_product(wave(ia:ib),wave(ia:ib))/NWAVE)
nslots=1
if(width.gt.0.0) call filt8(f0,nslots,width,wave)
if(snrdb.lt.90) then
do i=1,NMAX !Add gaussian noise at specified SNR
xnoise=gran()
wave(i)=wave(i) + xnoise
enddo
endif
fac=32767.0
rms=100.0
if(snrdb.ge.90.0) iwave(1:NMAX)=nint(fac*wave)
if(snrdb.lt.90.0) iwave(1:NMAX)=nint(rms*wave)
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