mirror of https://github.com/saitohirga/WSJT-X.git
105 lines
3.4 KiB
Fortran
105 lines
3.4 KiB
Fortran
program ft8sim
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! Generate simulated data for a 15-second HF/6m mode using 8-FSK.
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! Output is saved to a *.wav file.
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use wavhdr
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include 'ft8_params.f90' !Set various constants
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type(hdr) h !Header for .wav file
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character arg*12,fname*17
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character msg*22,msgsent*22
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complex c0(0:NMAX-1)
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complex c(0:NMAX-1)
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integer itone(NN)
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integer*1 msgbits(KK)
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integer*2 iwave(NMAX) !Generated full-length waveform
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! Get command-line argument(s)
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nargs=iargc()
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if(nargs.ne.6) then
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print*,'Usage: ft8sim "message" DT fdop del nfiles snr'
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print*,'Example: ft8sim "K1ABC W9XYZ EN37" 0.0 0.1 1.0 10 -18'
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go to 999
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endif
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call getarg(1,msg) !Message to be transmitted
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call getarg(2,arg)
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read(arg,*) xdt !Time offset from nominal (s)
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call getarg(3,arg)
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read(arg,*) fspread !Watterson frequency spread (Hz)
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call getarg(4,arg)
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read(arg,*) delay !Watterson delay (ms)
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call getarg(5,arg)
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read(arg,*) nfiles !Number of files
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call getarg(6,arg)
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read(arg,*) snrdb !SNR_2500
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twopi=8.0*atan(1.0)
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fs=12000.0 !Sample rate (Hz)
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dt=1.0/fs !Sample interval (s)
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tt=NSPS*dt !Duration of symbols (s)
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baud=1.0/tt !Keying rate (baud)
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bw=8*baud !Occupied bandwidth (Hz)
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txt=NZ*dt !Transmission length (s)
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bandwidth_ratio=2500.0/(fs/2.0)
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sig=sqrt(2*bandwidth_ratio) * 10.0**(0.05*snrdb)
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if(snrdb.gt.90.0) sig=1.0
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txt=NN*NSPS/12000.0
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call genft8(msg,msgsent,msgbits,itone) !Source-encode, then get itone()
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write(*,1000) f0,xdt,txt,snrdb,bw,msgsent
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1000 format('f0:',f9.3,' DT:',f6.2,' TxT:',f6.1,' SNR:',f6.1, &
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' BW:',f4.1,2x,a22)
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write(*,'(28i1,1x,28i1)') msgbits(1:56)
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write(*,'(16i1)') msgbits(57:72)
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write(*,'(3i1)') msgbits(73:75)
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write(*,'(12i1)') msgbits(76:87)
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! call sgran()
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c=0.
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do ifile=1,nfiles
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c0=0.
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do isig=1,25
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f0=(isig+2)*100.0
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phi=0.0
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k=-1 + nint(xdt+0.5/dt)
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do j=1,NN !Generate complex waveform
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dphi=twopi*(f0+itone(j)*baud)*dt
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if(k.eq.0) phi=-dphi
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do i=1,NSPS
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k=k+1
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phi=phi+dphi
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if(phi.gt.twopi) phi=phi-twopi
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xphi=phi
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if(k.ge.0 .and. k.lt.NMAX) c0(k)=cmplx(cos(xphi),sin(xphi))
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enddo
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enddo
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if(fspread.ne.0.0 .or. delay.ne.0.0) call watterson(c,NMAX,fs,delay,fspread)
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c=c+c0
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enddo
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c=c*sig
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if(snrdb.lt.90) then
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do i=0,NMAX-1 !Add gaussian noise at specified SNR
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xnoise=gran()
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ynoise=gran()
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c(i)=c(i) + cmplx(xnoise,ynoise)
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enddo
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endif
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fac=32767.0
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rms=100.0
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if(snrdb.ge.90.0) iwave(1:NMAX)=nint(fac*real(c))
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if(snrdb.lt.90.0) iwave(1:NMAX)=nint(rms*real(c))
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h=default_header(12000,NMAX)
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write(fname,1102) ifile
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1102 format('000000_',i6.6,'.wav')
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open(10,file=fname,status='unknown',access='stream')
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write(10) h,iwave !Save to *.wav file
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close(10)
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write(*,1110) ifile,xdt,f0,snrdb,fname
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1110 format(i4,f7.2,f8.2,f7.1,2x,a17)
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enddo
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999 end program ft8sim
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