mirror of https://github.com/saitohirga/WSJT-X.git
130 lines
3.9 KiB
Fortran
130 lines
3.9 KiB
Fortran
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program ft4sim_mult
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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' !FT4 protocol constants
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parameter (NWAVE=NN*NSPS)
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parameter (NZZ=15*12000) !Length of .wav file, 180,000 i*2 samples
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type(hdr) h !Header for .wav file
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character arg*12,fname*17,cjunk*4
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character msg37*37,msgsent37*37,c77*77
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real wave(NZZ)
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real tmp(NZZ)
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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*2 iwave(NZZ) !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.2) then
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print*,'Usage: ft4sim nsigs nfiles'
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print*,'Example: ft4sim 20 8 '
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go to 999
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endif
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call getarg(1,arg)
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read(arg,*) nsigs !Number of signals
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call getarg(2,arg)
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read(arg,*) nfiles !Number of files
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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 unsmoothed symbols (s)
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baud=1.0/tt !Keying rate (baud)
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txt=NZ*dt !Transmission length (s) without ramp up/down
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bandwidth_ratio=2500.0/(fs/2.0)
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txt=NN*NSPS/12000.0
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xdtmax=10.0 - 0.086
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! Compute 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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open(10,file='messages.txt',status='old',err=998)
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do ifile=1,nfiles
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1 read(10,1001,end=999) cjunk,n
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1001 format(a4,i2)
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if(cjunk.ne.'File' .or. n.ne.ifile) go to 1
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wave=0.
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write(fname,1002) ifile
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1002 format('000000_',i6.6,'.wav')
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do isig=1,nsigs
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read(10,1003,end=100) cjunk,isnr,xdt0,ifreq,msg37
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1003 format(a4,30x,i3,f5.1,i5,1x,a37)
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if(cjunk.eq.'File') go to 100
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if(isnr.lt.-16) isnr=-16
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f0=ifreq*93.75/50.0
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call random_number(r)
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xdt=r*xdtmax
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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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call genft4(msg37,0,msgsent37,itone)
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! Compute the smoothed 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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! Calculate and insert the audio waveform
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phi=0.0
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dphi=dphi+twopi*f0*dt
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tmp=0.
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k0=nint((xdt+0.043)/dt)
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k=k0-1
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do j=0,NMAX-1
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k=k+1
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tmp(k)=sin(phi)
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phi=mod(phi+dphi(j),twopi)
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enddo
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k1=k
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! Compute the ramp-up and ramp-down symbols
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tmp(k0-NSPS:k0-1)=tmp(k0-NSPS:k0-1) * &
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(1.0-cos(twopi*(/(i,i=0,NSPS-1)/)/(2.0*NSPS)))/2.0
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tmp(k1+1:k1+NSPS)=tmp(k1+1:k1+NSPS) * &
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(1.0+cos(twopi*(/(i,i=0,NSPS-1)/)/(2.0*NSPS)))/2.0
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! Insert this signal into wave() array
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sig=sqrt(2*bandwidth_ratio) * 10.0**(0.05*isnr)
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wave=wave + sig*tmp
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write(*,1100) fname,isig,isnr,nint(f0),msg37
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1100 format(a17,i4,i5,i6,2x,a37)
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enddo ! isig
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100 backspace 10
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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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gain=30.0
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wave=gain*wave
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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,NZZ)
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open(12,file=fname,status='unknown',access='stream')
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write(12) h,iwave !Save to *.wav file
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close(12)
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print*,' '
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enddo ! ifile
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go to 999
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998 print*,'Cannot open file "messages.txt"'
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999 end program ft4sim_mult
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