program wspr5d ! Decode WSPR-LF data read from *.c5 or *.wav files. ! WSPR-LF is a potential WSPR-like mode intended for use at LF and MF. ! It uses an LDPC (300,60) code, OQPSK modulation, and 5 minute T/R sequences. ! ! Still to do: find and decode more than one signal in the specified passband. include 'wsprlf_params.f90' parameter (NMAX=300*12000) character arg*8,message*22,cbits*50,infile*80,fname*16,datetime*11 character*120 data_dir complex csync(0:NZ-1) !Sync symbols only, from cbb complex c(0:NZ-1) !Complex waveform complex cd(0:412*16-1) !Complex waveform complex ca(0:412*16-1) !Complex waveform real*8 fMHz real rxdata(ND),llr(ND) !Soft symbols real pp(32) !Shaped pulse for OQPSK real ps(0:7),sbits(412) integer id(NS+ND) !NRZ values (+/-1) for Sync and Data integer isync(48) !Long sync vector integer ib13(13) !Barker 13 code integer ihdr(11) integer*8 n8 integer*2 iwave(NMAX) !Generated full-length waveform integer*1 idat(7) integer*1 decoded(KK),apmask(ND),cw(ND) integer*1 hbits(412),ebits(411),bits(5) data ib13/1,1,1,1,1,-1,-1,1,1,-1,1,-1,1/ nargs=iargc() if(nargs.lt.2) then print*,'Usage: wspr5d [-a ] [-f fMHz] file1 [file2 ...]' go to 999 endif iarg=1 data_dir="." call getarg(iarg,arg) if(arg(1:2).eq.'-a') then call getarg(iarg+1,data_dir) iarg=iarg+2 endif call getarg(iarg,arg) if(arg(1:2).eq.'-f') then call getarg(iarg+1,arg) read(arg,*) fMHz iarg=iarg+2 endif open(13,file=trim(data_dir)//'/ALL_WSPR.TXT',status='unknown', & position='append') maxn=8 !Default value twopi=8.0*atan(1.0) fs=NSPS*12000.0/NSPS0 !Sample rate dt=1.0/fs !Sample interval (s) tt=NSPS*dt !Duration of "itone" symbols (s) ts=2*NSPS*dt !Duration of OQPSK symbols (s) baud=1.0/tt !Keying rate for "itone" symbols (baud) txt=NZ*dt !Transmission length (s) do i=1,32 !Half-sine pulse shape pp(i)=sin(0.5*(i-1)*twopi/(32)) enddo n8=z'cbf089223a51' do i=1,48 isync(i)=-1 if(iand(n8,1).eq.1) isync(i)=1 n8=n8/2 enddo ! Define array id() for sync symbols id=0 do j=1,48 !First group of 48 id(2*j-1)=2*isync(j) enddo do j=1,13 !Barker 13 code id(j+96)=2*ib13(j) enddo do j=1,48 !Second group of 48 id(2*j+109)=2*isync(j) enddo csync=0. do j=1,205 if(abs(id(j)).eq.2) then ia=nint((j-0.5)*N2) ib=ia+N2-1 csync(ia:ib)=pp*id(j)/abs(id(j)) endif enddo do ifile=iarg,nargs call getarg(ifile,infile) open(10,file=infile,status='old',access='stream') j1=index(infile,'.c5') j2=index(infile,'.wav') if(j1.gt.0) then read(10,end=999) fname,ntrmin,fMHz,c read(fname(8:11),*) nutc write(datetime,'(i11)') nutc else if(j2.gt.0) then read(10,end=999) ihdr,iwave read(infile(j2-4:j2-1),*) nutc datetime=infile(j2-11:j2-1) call wspr5_downsample(iwave,c) else print*,'Wrong file format?' go to 999 endif close(10) fa=100.0 fb=170.0 call getfc1w(c,fs,fa,fb,fc1,xsnr) !First approx for freq call getfc2w(c,csync,fs,fc1,fc2,fc3) !Refined freq !write(*,*) fc1+fc2 call downsample(c,fc1+fc2,cd) do ncoh=1,0,-1 do is=0,9 idt=is/2 if( mod(is,2).eq. 1 ) idt=-is/2 xdt=idt/22.222 k=-1 ca=cshift(cd,22+idt) do i=1,408,4 k=k+2 j=(i+1)*16 call mskseqdet(ca(j),pp,id(k),bits,ps,ncoh) r1=max(ps(1),ps(3),ps(5),ps(7))-max(ps(0),ps(2),ps(4),ps(6)) r2=max(ps(2),ps(3),ps(6),ps(7))-max(ps(0),ps(1),ps(4),ps(5)) r4=max(ps(4),ps(5),ps(6),ps(7))-max(ps(0),ps(1),ps(2),ps(3)) hbits(i:i+4)=bits sbits(i:i+4)=bits sbits(i+1)=r4 sbits(i+2)=r2 if( id(k+1) .ne. 0 ) sbits(i+2)=id(k+1)*25 sbits(i+3)=r1 enddo j=1 do i=1,205 if( abs(id(i)) .ne. 2 ) then rxdata(j)=sbits(2*i-1) j=j+1 endif enddo do i=1,204 rxdata(j)=sbits(2*i) j=j+1 enddo rxav=sum(rxdata)/ND rx2av=sum(rxdata*rxdata)/ND rxsig=sqrt(rx2av-rxav*rxav) rxdata=rxdata/rxsig sigma=0.84 llr=2*rxdata/(sigma*sigma) apmask=0 max_iterations=40 ifer=0 nbadcrc=0 call bpdecode300(llr,apmask,max_iterations,decoded,niterations,cw) if(niterations.lt.0) call osd300(llr,3,decoded,niterations,cw) if(niterations.ge.0) call chkcrc10(decoded,nbadcrc) if(niterations.lt.0 .or. nbadcrc.ne.0) ifer=1 if( ifer.eq.0 ) then write(cbits,1200) decoded(1:50) 1200 format(50i1) read(cbits,1202) idat 1202 format(6b8,b2) idat(7)=ishft(idat(7),6) call wqdecode(idat,message,itype) nsnr=nint(xsnr) freq=fMHz + 1.d-6*(fc1+fc2) nfdot=0 write(13,1210) datetime,0,nsnr,xdt,freq,message,nfdot 1210 format(a11,2i4,f6.2,f12.7,2x,a22,i3) write(*,1212) datetime(8:11),nsnr,xdt,freq,nfdot,message,'*' 1212 format(a4,i4,f5.1,f11.6,i3,2x,a22,a1) goto 888 endif enddo enddo 888 enddo write(*,1120) 1120 format("") 999 end program wspr5d subroutine mskseqdet(cdat,pp,bsync,bestbits,cmbest,ncoh) complex cdat(16*4),cbest(16*4),cideal(16*4) complex cdf(16*4),cfac real cm(0:7),cmbest(0:7) real pp(32) integer*1 bits(5),bestbits(5),sgn(5) integer bsync(3) twopi=8.0*atan(1.0) dt=30.0*18.0/12000.0 cmax=0; fbest=0.0; idfmax=40 if( ncoh .eq. 1 ) idfmax=0 do idf=0,idfmax if( mod(idf,2).eq.1 ) deltaf=idf/2*0.02 if( mod(idf,2).eq.1 ) deltaf=-(idf+1)/2*0.02 dphi=twopi*deltaf*dt cfac=cmplx(cos(dphi),sin(dphi)) cdf=1.0 do i=2,16*4 cdf(i)=cdf(i-1)*cfac enddo cm=0 ibflag=0 do i=0,7 bits(1)=(bsync(1)+2)/4 bits(2)=iand(i/4,1) bits(3)=iand(i/2,1) if( bsync(2).ne.0 ) then ! force the barker bits bits(3)=(bsync(2)+2)/4 endif bits(4)=iand(i/1,1) bits(5)=(bsync(3)+2)/4 sgn=2*bits-1 cideal(1:16)=cmplx(sgn(1)*pp(17:32),sgn(2)*pp(1:16)) cideal(17:32)=cmplx(sgn(3)*pp(1:16),sgn(2)*pp(17:32)) cideal(33:48)=cmplx(sgn(3)*pp(17:32),sgn(4)*pp(1:16)) cideal(49:64)=cmplx(sgn(5)*pp(1:16),sgn(4)*pp(17:32)) cideal=cideal*cdf cm(i)=abs(sum(cdat*conjg(cideal)))/1.e3 if( cm(i) .gt. cmax ) then ibflag=1 cmax=cm(i) bestbits=bits cbest=cideal fbest=deltaf endif enddo if( ibflag .eq. 1 ) then ! new best found cmbest=cm endif enddo end subroutine mskseqdet subroutine downsample(ci,f0,co) parameter(NI=412*288,NO=NI/18) complex ci(0:NI-1),ct(0:NI-1) complex co(0:NO-1) df=400.0/NI ct=ci call four2a(ct,NI,1,-1,1) !r2c FFT to freq domain i0=nint(f0/df) co=0.0 co(0)=ct(i0) b=4.0 do i=1,NO/2 arg=(i*df/b)**2 filt=exp(-arg) co(i)=ct(i0+i)*filt co(NO-i)=ct(i0-i)*filt enddo co=co/NO call four2a(co,NO,1,1,1) !c2c FFT back to time domain return end subroutine downsample