mirror of https://github.com/saitohirga/WSJT-X.git
141 lines
2.8 KiB
Fortran
141 lines
2.8 KiB
Fortran
program t1
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parameter (NSPM=1404)
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complex csig(0:NSPM-1)
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complex c(0:NSPM-1)
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complex cnoise(0:NSPM-1)
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complex cd(0:11,0:3)
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complex z,zmax
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integer itone(234)
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real r(234)
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real ss(0:3)
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character*12 arg
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nargs=iargc()
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if(nargs.ne.3) then
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print*,'Usage: t1 nsymtest snrdb iters'
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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,*) nsymtest
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call getarg(2,arg)
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read(arg,*) snrdb
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call getarg(3,arg)
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read(arg,*) iters
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call init_random_seed() ! seed Fortran RANDOM_NUMBER generator
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call sgran() ! see C rand generator (used in gran)
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call random_number(r)
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itone=0
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where(r.gt.0.5) itone=1
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twopi=8.0*atan(1.0)
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fmid=1500.0
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f0=fmid-500.
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f1=fmid+500.
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dt=1.0/12000.0
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phi=0.
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do n=0,3
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k=-1
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dphi=twopi*f0*dt
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if(n.ge.2) dphi=twopi*f1*dt
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do i=0,5
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k=k+1
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phi=phi+dphi
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if(phi.gt.twopi) phi=phi-twopi
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cd(k,n)=cmplx(cos(phi),sin(phi))
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enddo
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dphi=twopi*f0*dt
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if(mod(n,2).eq.1) dphi=twopi*f1*dt
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do i=6,11
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k=k+1
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phi=phi+dphi
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if(phi.gt.twopi) phi=phi-twopi
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cd(k,n)=cmplx(cos(phi),sin(phi))
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enddo
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enddo
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! do k=0,11
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! write(13,1000) k,cd(k,0:3)
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!1000 format(i4,8f9.3)
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!enddo
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! Generate signal waveform
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k=-1
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phi=0.
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do j=1,234
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dphi=twopi*f0*dt
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if(itone(j).eq.1) dphi=twopi*f1*dt
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do i=1,6
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k=k+1
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phi=phi+dphi
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if(phi.gt.twopi) phi=phi-twopi
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csig(k)=cmplx(cos(phi),sin(phi))
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! write(14,1000) k,csig(k)
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enddo
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enddo
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write(*,1010)
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1010 format(' S/N (S+N)/N BER'/'----------------------')
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isnra=10
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isnrb=-3
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nsyms=234
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do isnr=isnra,isnrb,-1
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snr=10.0**(0.1*isnr)
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if(snrdb.ne.0.0) snr=10.0**(0.1*snrdb)
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fac=1.0/sqrt(snr)
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nsumerr=0
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do iter=1,iters
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do i=0,NSPM-1
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x=gran()
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y=gran()
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cnoise(i)=cmplx(x,y)
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enddo
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c=csig + fac*cnoise
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nerr=0
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n1=2
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nstep=2
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iz=5
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if(nsymtest.eq.2) then
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n1=3
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nstep=1
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iz=11
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endif
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do j=1,nsyms
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smax=0.
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do n=0,n1,nstep
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s=0.
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k=6*(j-1)
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do i=0,iz
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s=s + aimag(c(k+i))*aimag(cd(i,n))
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enddo
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ss(n)=s
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if(abs(s).gt.abs(smax)) then
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smax=s
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npk=n
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endif
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enddo
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sym=max(abs(ss(2)),abs(ss(3))) - max(abs(ss(0)),abs(ss(1)))
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! ibit=npk/2
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ibit=0
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if(sym.ge.0.0) ibit=1
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if(ibit.ne.itone(j)) nerr=nerr+1
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enddo
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nsumerr=nsumerr+nerr
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enddo
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write(*,1020) 10.0*log10(snr),10.0*log10(snr+1.0), &
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float(nsumerr)/(nsyms*iters)
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1020 format(f5.1,f7.1,f9.3)
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if(snrdb.ne.0.0) exit
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enddo
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999 end program t1
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