mirror of https://github.com/saitohirga/WSJT-X.git
126 lines
3.9 KiB
Fortran
126 lines
3.9 KiB
Fortran
program ft4sim
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! Generate simulated signals for experimental "FT4" mode
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use wavhdr
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use packjt77
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include 'ft4_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 msg37*37,msgsent37*37
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character c77*77
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complex c0(0:NMAX-1)
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complex c(0:NMAX-1)
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real wave(NMAX)
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integer itone(NN)
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integer*1 msgbits(77)
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integer*2 iwave(NMAX) !Generated full-length waveform
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integer icos4(4)
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data icos4/0,1,3,2/
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! Get command-line argument(s)
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nargs=iargc()
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if(nargs.ne.7) then
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print*,'Usage: ft4sim "message" f0 DT fdop del nfiles snr'
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print*,'Examples: ft4sim "CQ W9XYZ EN37" 1500 0.0 0.1 1.0 10 -15'
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print*,' ft4sim "K1ABC W9XYZ R 539 WI" 1500 0.0 0.1 1.0 10 -15'
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go to 999
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endif
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call getarg(1,msg37) !Message to be transmitted
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call getarg(2,arg)
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read(arg,*) f0 !Frequency (only used for single-signal)
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call getarg(3,arg)
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read(arg,*) xdt !Time offset from nominal (s)
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call getarg(4,arg)
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read(arg,*) fspread !Watterson frequency spread (Hz)
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call getarg(5,arg)
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read(arg,*) delay !Watterson delay (ms)
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call getarg(6,arg)
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read(arg,*) nfiles !Number of files
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call getarg(7,arg)
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read(arg,*) snrdb !SNR_2500
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nfiles=abs(nfiles)
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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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hmod=1.0 !Modulation index (0.5 is MSK, 1.0 is FSK)
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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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txt=NZ2*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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! Source-encode, then get itone()
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i3=-1
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n3=-1
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call pack77(msg37,i3,n3,c77)
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read(c77,'(77i1)') msgbits
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call genft4(msg37,0,msgsent37,msgbits,itone)
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write(*,*)
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write(*,'(a9,a37,3x,a7,i1,a1,i1)') 'Message: ',msgsent37,'i3.n3: ',i3,'.',n3
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write(*,1000) f0,xdt,txt,snrdb
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1000 format('f0:',f9.3,' DT:',f6.2,' TxT:',f6.1,' SNR:',f6.1)
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write(*,*)
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if(i3.eq.1) then
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write(*,*) ' mycall hiscall hisgrid'
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write(*,'(28i1,1x,i1,1x,28i1,1x,i1,1x,i1,1x,15i1,1x,3i1)') msgbits(1:77)
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else
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write(*,'(a14)') 'Message bits: '
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write(*,'(77i1)') msgbits
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endif
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write(*,*)
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write(*,'(a17)') 'Channel symbols: '
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write(*,'(76i1)') itone
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write(*,*)
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call sgran()
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fsample=12000.0
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icmplx=1
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call gen_ft4wave(itone,NN,NSPS,fsample,f0,c0,wave,icmplx,NMAX)
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k=nint((xdt+0.5)/dt)-NSPS
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c0=cshift(c0,-k)
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if(k.gt.0) c0(0:k-1)=0.0
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if(k.lt.0) c0(NMAX+k:NMAX-1)=0.0
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do ifile=1,nfiles
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c=c0
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if(fspread.ne.0.0 .or. delay.ne.0.0) call watterson(c,NMAX,NZ,fs,delay,fspread)
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c=sig*c
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wave=real(c)
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peak=maxval(abs(wave))
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nslots=1
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if(snrdb.lt.90) then
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do i=1,NMAX !Add gaussian noise at specified SNR
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xnoise=gran()
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wave(i)=wave(i) + xnoise
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enddo
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endif
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gain=100.0
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if(snrdb.lt.90.0) then
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wave=gain*wave
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else
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datpk=maxval(abs(wave))
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fac=32766.9/datpk
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wave=fac*wave
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endif
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if(any(abs(wave).gt.32767.0)) print*,"Warning - data will be clipped."
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iwave=nint(wave)
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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 ft4sim
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