2019-06-12 11:31:35 -04:00
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program rtty_spec
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! Generate simulated data for standard RTTY and WSJT-X modes FT8, FT4
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use wavhdr
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use packjt
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parameter (NMAX=15*12000)
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type(hdr) h
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complex cwave(NMAX)
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real wave(NMAX)
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real*4 dat(NMAX) !Generated waveform
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integer*2 iwave(NMAX) !Generated waveform
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integer itone(680) !Channel symbols (values 0-1, 0-3, 0-7)
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integer*1 msgbits(77)
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character*37 msg37,msgsent37
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character*8 arg
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nargs=iargc()
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if(nargs.ne.1) then
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print*,'Usage: rtty_spec <snr>'
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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,*) snrdb !S/N in dB (2500 hz reference BW)
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rmsdb=25.
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rms=10.0**(0.05*rmsdb)
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sig=10.0**(0.05*snrdb)
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npts=NMAX
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do i=1,NMAX !Generate gaussian noise
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dat(i)=gran()
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enddo
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! Add the RTTY signal
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fsample=12000.0 !Sample rate (Hz)
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dt=1.0/fsample !Sample interval (s)
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twopi=8.0*atan(1.0)
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phi=0.
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dphi=0.
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j0=-1
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do i=6001,NMAX-6000
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j=nint(i*dt/0.022)
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if(j.ne.j0) then
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f0=1415.0
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call random_number(rr)
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if(rr.gt.0.5) f0=1585.0
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dphi=twopi*f0*dt
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j0=j
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endif
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phi=phi+dphi
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if(phi.gt.twopi) phi=phi-twopi
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dat(i)=dat(i) + sig*sin(phi)
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enddo
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2019-06-13 11:07:29 -04:00
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! FT8 signal (FSK)
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i3=0
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n3=0
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msg37='WB9XYZ KA2ABC FN42'
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call genft8(msg37,i3,n3,msgsent37,msgbits,itone)
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nsym=79
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nsps=1920
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bt=99.0
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f0=3500.0
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icmplx=0
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nwave=nsym*nsps
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call gen_ft8wave(itone,nsym,nsps,bt,fsample,f0,cwave,wave,icmplx,nwave)
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dat(6001:6000+nwave)=dat(6001:6000+nwave) + sig*wave(1:nwave)
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! FT8 signal (GFSK)
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2019-06-12 11:31:35 -04:00
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i3=0
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n3=0
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msg37='WB9XYZ KA2ABC FN42'
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call genft8(msg37,i3,n3,msgsent37,msgbits,itone)
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nsym=79
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nsps=1920
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bt=2.0
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2019-06-13 11:07:29 -04:00
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f0=4000.0
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2019-06-12 11:31:35 -04:00
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icmplx=0
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nwave=nsym*nsps
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call gen_ft8wave(itone,nsym,nsps,bt,fsample,f0,cwave,wave,icmplx,nwave)
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dat(6001:6000+nwave)=dat(6001:6000+nwave) + sig*wave(1:nwave)
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! Add the FT4 signal
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ichk=0
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call genft4(msg37,ichk,msgsent37,msgbits,itone)
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nsym=103
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nsps=576
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2019-06-13 11:07:29 -04:00
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f0=4500.0
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2019-06-12 11:31:35 -04:00
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icmplx=0
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nwave=(nsym+2)*nsps
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call gen_ft4wave(itone,nsym,nsps,fsample,f0,cwave,wave,icmplx,nwave)
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dat(6001:6000+nwave)=dat(6001:6000+nwave) + sig*wave(1:nwave)
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2019-06-13 11:07:29 -04:00
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2019-06-12 11:31:35 -04:00
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h=default_header(12000,NMAX)
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2019-06-13 11:07:29 -04:00
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datmax=maxval(abs(dat))
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iwave=nint(32767.0*dat/datmax)
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2019-06-12 11:31:35 -04:00
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open(10,file='000000_000001.wav',access='stream',status='unknown')
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write(10) h,iwave
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close(10)
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999 end program rtty_spec
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