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https://github.com/saitohirga/WSJT-X.git
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159 lines
4.9 KiB
Fortran
159 lines
4.9 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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parameter (NWAVE=NN*NSPS)
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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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real dphi(0:NMAX-1)
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real pulse(3*NSPS)
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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.8) then
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print*,'Usage: ft4sim "message" f0 DT fdop del width nfiles snr'
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print*,'Examples: ft4sim "K1ABC W9XYZ EN37" 1500.0 0.0 0.1 1.0 0 10 -18'
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print*,' ft4sim "WA9XYZ/R KA1ABC/R FN42" 1500.0 0.0 0.1 1.0 0 10 -18'
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print*,' ft4sim "K1ABC RR73; W9XYZ <KH1/KH7Z> -11" 300 0 0 0 25 1 -10'
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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,*) width !Filter transition width (Hz)
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call getarg(7,arg)
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read(arg,*) nfiles !Number of files
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call getarg(8,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=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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! 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,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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! The filtered frequency pulse
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do i=1,3*NSPS
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tt=(i-1.5*NSPS)/real(NSPS)
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pulse(i)=gfsk_pulse(1.0,tt)
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enddo
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! Define the instantaneous frequency waveform
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dphi_peak=twopi*hmod/real(NSPS)
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dphi=0.0
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do j=1,NN
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ib=(j-1)*NSPS
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ie=ib+3*NSPS-1
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dphi(ib:ie)=dphi(ib:ie)+dphi_peak*pulse*itone(j)
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enddo
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phi=0.0
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c0=0.0
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dphi=dphi+twopi*f0*dt
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do j=0,NMAX-1
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c0(j)=cmplx(cos(phi),sin(phi))
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phi=mod(phi+dphi(j),twopi)
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enddo
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c0(0:NSPS-1)=c0(0:NSPS-1)*(1.0-cos(twopi*(/(i,i=0,NSPS-1)/)/(2.0*NSPS)) )/2.0
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c0((NN+1)*NSPS:(NN+2)*NSPS-1)=c0((NN+1)*NSPS:(NN+2)*NSPS-1)*(1.0+cos(twopi*(/(i,i=0,NSPS-1)/)/(2.0*NSPS) ))/2.0
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c0((NN+2)*NSPS:)=0.
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k=nint((xdt+0.25)/dt)
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c0=cshift(c0,-k)
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ia=k
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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,NWAVE,fs,delay,fspread)
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c=sig*c
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ib=k
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wave=real(c)
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peak=maxval(abs(wave(ia:ib)))
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nslots=1
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if(width.gt.0.0) call filt8(f0,nslots,width,wave)
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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+2208)
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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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iwave(1:2208)=0
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write(10) iwave(1:2208) !Add 0.5 s of zeroes
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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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