WSJT-X/lib/superfox/synctest.f90

program synctest

! Generate and test sync waveforms for possible use in SuperFox signal.

  use wavhdr
  include "sfox_params.f90"
  type(hdr) h                            !Header for .wav file
  integer*2 iwave(NMAX)                  !Generated i*2 waveform
  real*4 xnoise(NMAX)                    !Random noise
  real*4 dat(NMAX)                       !Generated real data
  complex cdat(NMAX)                     !Generated complex waveform
  complex clo(NMAX)                      !Complex Local Oscillator
  complex cnoise(NMAX)                   !Complex noise
  complex crcvd(NMAX)                    !Signal as received
!  real xdat(ND)                          !Temporary: for generating idat
  integer*1 idat(ND)                     !Encoded data, 7-bit integers
  integer*1 jdat(ND)                     !Recovered hard-decision symbols
  character fname*17,arg*12
  
  nargs=iargc()
  if(nargs.ne.8) then
     print*,'Usage:   synctest   f0    DT fspread delay width nran nfiles snr'
     print*,'Example: synctest 1500.0 0.15   0.5   1.0   100    0    10   -10'
     go to 999
  endif
  call getarg(1,arg)
  read(arg,*) f0
  call getarg(2,arg)
  read(arg,*) xdt
  call getarg(3,arg)
  read(arg,*) fspread
  call getarg(4,arg)
  read(arg,*) delay
  call getarg(5,arg)
  read(arg,*) syncwidth
  call getarg(6,arg)
  read(arg,*) nran
  call getarg(7,arg)
  read(arg,*) nfiles
  call getarg(8,arg)
  read(arg,*) snrdb

  rms=100.
  fsample=12000.0                   !Sample rate (Hz)
  baud=12000.0/nsps                 !Keying rate, 11.719 baud for nsps=1024
  h=default_header(12000,NMAX)
  idummy=0
  bandwidth_ratio=2500.0/6000.0

! Generate random data symbols
  do i=1,ND
     call random_number(r)
     if(nran.eq.1) r=ran1(idummy)
     idat(i)=128*r
  enddo
  
! Generate cdat (SuperFox waveform) and clo (LO for sync detection)
  call gen_sfox(idat,f0,fsample,syncwidth,cdat,clo)

  do isnr=0,-30,-1
     snr=isnr
     if(snrdb.ne.0.0) snr=snrdb
     sig=sqrt(2*bandwidth_ratio)*10.0**(0.05*snr)
     if(snr.gt.90.0) sig=1.0
     ngoodsync=0
     ngood=0

     do ifile=1,nfiles
        xnoise=0.
        cnoise=0.
        if(snr.lt.90) then
           do i=1,NMAX                     !Generate Gaussian noise
              x=gran()
              y=gran()
              xnoise(i)=x
              cnoise(i)=cmplx(x,y)
           enddo
        endif

        f1=f0
        if(f0.eq.0.0) then
           f1=1500.0 + 200.0*(ran1(idummy)-0.5)
           xdt=2.0*(ran1(idummy)-0.5)
           call gen_sfox(idat,f1,fsample,syncwidth,cdat,clo)
        endif
        
        crcvd=0.
        crcvd(1:NMAX)=cshift(sig*cdat(1:NMAX),-nint(xdt*fsample)) + cnoise

        dat=aimag(sig*cdat(1:NMAX)) + xnoise     !Add generated AWGN noise
        fac=32767.0
        if(snr.ge.90.0) iwave(1:NMAX)=nint(fac*dat(1:NMAX))
        if(snr.lt.90.0) iwave(1:NMAX)=nint(rms*dat(1:NMAX))

        if(fspread.ne.0 .or. delay.ne.0) call watterson(crcvd,NMAX,NZ,fsample,&
             delay,fspread)

! Find signal freq and DT
        call sync_sf(crcvd,clo,snrdb,f,t)
        ferr=f-f1
        terr=t-xdt
        if(abs(ferr).lt.10.0 .or. abs(terr).lt.0.02) ngoodsync=ngoodsync+1

        call hard_symbols(crcvd,f,t,jdat)           !Get hard symbol values
        nharderr=count(jdat.ne.idat)                !Count hard errors
  
        if(snrdb.ne.0) then
           fname='000000_000001.wav'
           write(fname(8:13),'(i6.6)') ifile
           open(10,file=trim(fname),access='stream',status='unknown')
           write(10) h,iwave(1:NMAX)                !Save the .wav file
           close(10)
           write(*,1100) f1,xdt
1100       format(/'f0:',f7.1,'  xdt:',f6.2)
           write(*,1112) f,t
1112       format('f: ',f7.1,'   DT:',f6.2)
           write(*,1110) ferr,terr
1110       format('err:',f6.1,f12.2)
           write(*,1120) nharderr
1120       format('Hard errors:',i4)
        endif
        if(nharderr.le.38) ngood=ngood+1            !(125-49)/2 = 38
!        write(13,1200) ifile,snr,ferr,terr,nharderr
!1200    format(i5,3f10.3,i5)
     enddo  ! ifile
     fgoodsync=float(ngoodsync)/nfiles
     fgood=float(ngood)/nfiles
     if(isnr.eq.0) write(*,1300)
1300 format('    SNR     N  fsync  fgood'/  &
            '----------------------------')
     write(*,1310) snr,nfiles,fgoodsync,fgood
1310 format(f7.2,i6,2f7.2)
     if(snrdb.ne.0.0) exit
     if(fgoodsync.lt.0.5) exit
!     if(fgood.eq.0.0) exit
  enddo  ! isnr

999 end program synctest