176 lines
5.6 KiB
Fortran
176 lines
5.6 KiB
Fortran
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program wsprdpsksim
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! Generate simulated data for a 2-minute "WSPR-DPSK" mode. Output is saved
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! to a *.c2 or *.wav file.
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use wavhdr
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include 'wsprdpsk_params.f90' !Set various constants
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parameter (NMAX=120*12000)
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type(hdr) hwav !Header for .wav file
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character arg*12,fname*16
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character msg*22,msgsent*22
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complex c0(0:NMAX/NDOWN-1)
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complex c(0:NMAX/NDOWN-1)
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complex c0wav(0:NMAX-1)
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complex cwav(0:NMAX-1)
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real*8 fMHz
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integer imessage(NN)
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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.8) then
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print*,'Usage: wsprdpsksim "message" f0 DT fsp del nwav nfiles snr'
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print*,'Example: wsprdpsksim "K1ABC FN42 30" 50 0.0 0.1 1.0 1 10 -33'
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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,*) f0 !Freq relative to WSPR-band center (Hz)
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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,*) nwav !1 for *.wav file, 0 for *.c2 file
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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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twopi=8.0*atan(1.0)
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pi=twopi/2.0
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fs=12000.0/NDOWN
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dt=1.0/fs !Sample interval (s)
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tt=NSPS*dt !Duration of "itone" symbols (s)
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baud=1.0/tt !Keying rate for "itone" symbols (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(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*NSPS0/12000.0
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call genwsprdpsk(msg,msgsent,imessage) !Encode the message, get itone
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imessage=2*imessage-1
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write(*,1000) f0,xdt,txt,snrdb,fspread,delay,nfiles,msgsent
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1000 format('f0:',f9.3,' DT:',f6.2,' txt:',f6.1,' SNR:',f6.1, &
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' fspread:',f6.1,' delay:',f6.1,' nfiles:',i3,2x,a22)
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beta=1.0 ! excess bandwidth
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if(nwav.eq.0) then
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df=fs/(NMAX/NDOWN) !
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c=0
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bw=(1+beta)*baud/2.0
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bf=(1-beta)*baud/2.0
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iw=bw/df
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if=bf/df
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c(0:if-1)=1.0
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if(iw.gt.if) then
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do i=if,iw
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c(i)=((1.0+cos(pi*(i-if)/(iw-if)))/2.0)**0.5
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enddo
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endif
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c(NMAX/NDOWN-1:NMAX/NDOWN-iw:-1)=c(1:iw)
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istart=xdt/dt
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c0=0.0
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do i=1,NN
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c0(istart+(i-1)*200)=imessage(i)
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enddo
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call four2a(c0,NMAX/NDOWN,1,1,1)
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c0=c0*conjg(c)
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ic=f0/df
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c0=cshift(c0,ic)
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call four2a(c0,NMAX/NDOWN,1,-1,1)
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xx=sum(abs(c0(istart:istart+NN*200-1)**2))/(NN*200)
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c0=c0/sqrt(xx)
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call sgran()
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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 ) then
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call watterson(c,NMAX/NDOWN,fs,delay,fspread)
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endif
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c=c*sig
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if(snrdb.lt.90) then
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do i=0,NMAX/NDOWN-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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snrtest=sum(abs(c(istart:istart+NN*200-1)**2))/(NN*200)/2.0-1.0
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write(*,*) 'sample SNR: ',10*log10(snrtest)+10*log10(0.4/2.5)
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write(fname,1100) ifile
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1100 format('000000_',i4.4,'.c2')
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open(10,file=fname,status='unknown',access='stream')
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fMHz=10.1387d0
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nmin=2
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write(10) fname,nmin,fMHz,c !Save to *.c2 file
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close(10)
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enddo
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else
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fs=12000.0
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df=fs/NMAX
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dt=1/fs
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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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cwav=0
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bw=(1+beta)*baud/2.0
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bf=(1-beta)*baud/2.0
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iw=bw/df
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if=bf/df
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cwav(0:if-1)=1.0
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if(iw.gt.if) then
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do i=if,iw
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cwav(i)=((1.0+cos(pi*(i-if)/(iw-if)))/2.0)**0.5
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enddo
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endif
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cwav(NMAX-1:NMAX-iw:-1)=cwav(1:iw)
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istart=xdt/dt
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c0wav=0.0
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do i=1,NN
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c0wav(istart+(i-1)*200*NDOWN)=imessage(i)
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enddo
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call four2a(c0wav,NMAX,1,1,1)
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c0wav=c0wav*conjg(cwav)
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ic=f0/df
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c0wav=cshift(c0wav,-ic)
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call four2a(c0wav,NMAX,1,-1,1)
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xx=sum(abs(c0wav(istart:istart+NN*200*NDOWN-1))**2)/(NN*200*NDOWN)
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c0wav=c0wav/sqrt(xx)
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write(*,*) 'Peak power: ',maxval(abs(c0wav)**2)
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write(*,*) 'Average power: ',sum(abs(c0wav(istart:istart+NN*200*NDOWN-1))**2)/(NN*200*NDOWN)
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call sgran()
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do ifile=1,nfiles
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cwav=c0wav
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if( fspread .ne. 0.0 .or. delay .ne. 0.0 ) then
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call watterson(cwav,NMAX,fs,delay,fspread)
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endif
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cwav=cwav*sig
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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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iwave(i)=100*(real(cwav(i-1)) + xnoise)
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enddo
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endif
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snrtest=sum(real(iwave(istart:istart+NN*200*NDOWN-1)**2)/(NN*200*NDOWN))/100.0**2-1
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write(*,*) 'sample SNR: ',10*log10(snrtest)+10*log10(6.0/2.5)
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hwav=default_header(12000,NMAX)
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write(fname,1102) ifile
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1102 format('000000_',i4.4,'.wav')
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open(10,file=fname,status='unknown',access='stream')
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write(10) hwav,iwave !Save to *.wav file
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close(10)
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enddo
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endif
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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,a16)
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999 end program wsprdpsksim
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