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 (NDOWN=30) parameter (KK=60) parameter (ND=300) parameter (NS=109) parameter (NR=3) parameter (NN=NR+NS+ND) parameter (NSPS0=8640) parameter (NSPS=16) parameter (N2=2*NSPS) parameter (NZ=NSPS*NN) parameter (NZ400=288*NN) 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 c400(0:NZ400-1) !Complex waveform complex c(0:NZ-1) !Complex waveform complex cd(0:NZ-1) !Complex waveform complex ca(0:NZ-1) !Complex waveform complex zz real*8 fMHz real rxdata(ND),llr(ND) !Soft symbols real pp(32) !Shaped pulse for OQPSK real sbits(412),softbits(9) real fpks(20) 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),bits(13) 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,c400 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,c400) else print*,'Wrong file format?' go to 999 endif close(10) fa=100.0 fb=150.0 fs400=400.0 call getfc1(c400,fs400,fa,fb,fc1,xsnr) !First approx for freq !write(*,*) datetime,'initial guess ',fc1 npeaks=5 call getfc2(c400,npeaks,fs400,fc1,fpks) !Refined freq do idf=1,npeaks ! consider the top npeak peaks fc2=fpks(idf) call downsample(c400,fc1+fc2,cd) s2=sum(cd*conjg(cd))/(16*412) cd=cd/sqrt(s2) do is=0,8 ! dt search range is narrow, to save time. idt=is/2 if( mod(is,2).eq. 1 ) idt=-(is+1)/2 xdt=real(22+idt)/22.222 - 1.0 ca=cshift(cd,22+idt) do iseq=1,3 ! try sequence estimation lengths of 3, 6, and 9 bits. k=1-2*iseq nseq=iseq*3 do i=1,408,iseq*4 k=k+iseq*2 j=(i+1)*16 call mskseqdet(nseq,ca(j),pp,id(k),softbits,1,phase) hbits(i:i+iseq*4)=bits sbits(i:i+iseq*4)=bits sbits(i+1)=softbits(1) sbits(i+2)=softbits(2) if( id(k+1) .ne. 0 ) sbits(i+2)=id(k+1)*25 sbits(i+3)=softbits(3) if( iseq .ge. 2 ) then sbits(i+5)=softbits(4) sbits(i+6)=softbits(5) if( id(k+3) .ne. 0 ) sbits(i+6)=id(k+3)*25 sbits(i+7)=softbits(6) if( iseq .eq. 3 ) then sbits(i+9)=softbits(7) sbits(i+10)=softbits(8) if( id(k+5) .ne. 0 ) sbits(i+10)=id(k+5)*25 sbits(i+11)=softbits(9) endif endif 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 sigma=1.20 llr=2*rxdata/(sigma*sigma) apmask=0 max_iterations=40 ifer=0 nbadcrc=0 call bpdecode300(llr,apmask,max_iterations,decoded,niterations,cw) ! niterations will be equal to the Hamming distance between hard received word and the codeword 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,'*',idf,nseq,is,niterations 1212 format(a4,i4,f5.1,f11.6,i3,2x,a22,a1,i3,i3,i3,i4) goto 888 endif enddo !iseq enddo enddo 888 continue enddo write(*,1120) 1120 format("") 999 end program wspr5d subroutine getmetric(ib,ps,xmet) real ps(0:511) xm1=0 xm0=0 do i=0,511 if( iand(i/ib,1) .eq. 1 .and. ps(i) .gt. xm1 ) xm1=ps(i) if( iand(i/ib,1) .eq. 0 .and. ps(i) .gt. xm0 ) xm0=ps(i) enddo xmet=xm1-xm0 return end subroutine getmetric subroutine mskseqdet(ns,cdat,pp,bsync,softbits,ncoh,phase) ! ! Detect sequences of 3, 6, or 9 bits (ns). ! Sync bits are assumed to be known. ! complex cdat(16*12),cbest(16*12),cideal(16*12) complex cdf(16*12),cfac,zz real cm(0:511),cmbest(0:511) real pp(32),softbits(9) integer bit(13),bestbits(13),sgn(13) integer bsync(7) twopi=8.0*atan(1.0) dt=30.0*18.0/12000.0 cmax=0; fbest=0.0; np=2**ns-1 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*(ns-1) cdf(i)=cdf(i-1)*cfac enddo cm=0 ibflag=0 do i=0,np bit(1)=(bsync(1)+2)/4 bit(2)=iand(i/(2**(ns-1)),1) bit(3)=iand(i/(2**(ns-2)),1) if( bsync(2).ne.0 ) then ! force the barker bits bit(3)=(bsync(2)+2)/4 endif bit(4)=iand(i/(2**(ns-3)),1) bit(5)=(bsync(3)+2)/4 if( ns .ge. 6 ) then bit(6)=iand(i/(2**(ns-4)),1) bit(7)=iand(i/(2**(ns-5)),1) if( bsync(4).ne.0 ) then ! force the barker bits bit(7)=(bsync(4)+2)/4 endif bit(8)=iand(i/(2**(ns-6)),1) bit(9)=(bsync(5)+2)/4 if( ns .eq. 9 ) then bit(10)=iand(i/4,1) bit(11)=iand(i/2,1) if( bsync(6).ne.0 ) then ! force the barker bits bit(11)=(bsync(6)+2)/4 endif bit(12)=iand(i/1,1) bit(13)=(bsync(7)+2)/4 endif endif sgn=2*bit-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)) if( ns .ge. 6 ) then cideal(65:80) =cmplx(sgn(5)*pp(17:32),sgn(6)*pp(1:16)) cideal(81:96) =cmplx(sgn(7)*pp(1:16),sgn(6)*pp(17:32)) cideal(97:112) =cmplx(sgn(7)*pp(17:32),sgn(8)*pp(1:16)) cideal(113:128)=cmplx(sgn(9)*pp(1:16),sgn(8)*pp(17:32)) if( ns .eq. 9 ) then cideal(129:144) =cmplx(sgn(9)*pp(17:32),sgn(10)*pp(1:16)) cideal(145:160) =cmplx(sgn(11)*pp(1:16),sgn(10)*pp(17:32)) cideal(161:176) =cmplx(sgn(11)*pp(17:32),sgn(12)*pp(1:16)) cideal(177:192)=cmplx(sgn(13)*pp(1:16),sgn(12)*pp(17:32)) endif endif cideal=cideal*cdf cm(i)=abs(sum(cdat(1:64*ns/3)*conjg(cideal(1:64*ns/3))))/1.e3 if( cm(i) .gt. cmax ) then ibflag=1 cmax=cm(i) bestbits=bit cbest=cideal fbest=deltaf zz=sum(cdat*conjg(cbest))/1.e3 phase=atan2(imag(zz),real(zz)) endif enddo if( ibflag .eq. 1 ) then ! new best found cmbest=cm endif enddo softbits=0.0 call getmetric(1,cmbest,softbits(ns)) call getmetric(2,cmbest,softbits(ns-1)) call getmetric(4,cmbest,softbits(ns-2)) if( ns .ge. 6 ) then call getmetric(8,cmbest,softbits(ns-3)) call getmetric(16,cmbest,softbits(ns-4)) call getmetric(32,cmbest,softbits(ns-5)) if( ns .eq. 9 ) then call getmetric(64,cmbest,softbits(3)) call getmetric(128,cmbest,softbits(2)) call getmetric(256,cmbest,softbits(1)) endif endif 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) !c2c FFT to freq domain i0=nint(f0/df) co=0.0 co(0)=ct(i0) b=3.0 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 subroutine getfc1(c,fs,fa,fb,fc1,xsnr) ! include 'wsprlf_params.f90' parameter (NZ=288*412) parameter (NSPS=288) parameter (N2=2*NSPS) parameter (NFFT1=16*NSPS) parameter (NH1=NFFT1/2) complex c(0:NZ-1) !Complex waveform complex c2(0:NFFT1-1) !Short spectra real s(-NH1+1:NH1) !Coarse spectrum nspec=NZ/N2 df1=fs/NFFT1 s=0. do k=1,nspec ia=(k-1)*N2 ib=ia+N2-1 c2(0:N2-1)=c(ia:ib) c2(N2:)=0. call four2a(c2,NFFT1,1,-1,1) do i=0,NFFT1-1 j=i if(j.gt.NH1) j=j-NFFT1 s(j)=s(j) + real(c2(i))**2 + aimag(c2(i))**2 enddo enddo ! call smo121(s,NFFT1) smax=0. ipk=0 fc1=0. ia=nint(fa/df1) ib=nint(fb/df1) do i=ia,ib f=i*df1 if(s(i).gt.smax) then smax=s(i) ipk=i fc1=f endif ! write(51,3001) f,s(i),db(s(i)) ! 3001 format(f10.3,e12.3,f10.3) enddo ! The following is for testing SNR calibration: sp3n=(s(ipk-1)+s(ipk)+s(ipk+1)) !Sig + 3*noise base=(sum(s)-sp3n)/(NFFT1-3.0) !Noise per bin psig=sp3n-3*base !Sig only pnoise=(2500.0/df1)*base !Noise in 2500 Hz xsnr=db(psig/pnoise) xsnr=xsnr+5.0 return end subroutine getfc1 subroutine getfc2(c,npeaks,fs,fc1,fpks) ! include 'wsprlf_params.f90' parameter (NZ=288*412) parameter (NSPS=288) parameter (N2=2*NSPS) parameter (NFFT1=16*NSPS) parameter (NH1=NFFT1/2) complex c(0:NZ-1) !Complex waveform complex cs(0:NZ-1) !For computing spectrum real a(5) real freqs(413),sp2(413),fpks(npeaks) integer pkloc(1) df=fs/NZ baud=fs/NSPS a(1)=-fc1 a(2:5)=0. call twkfreq1(c,NZ,fs,a,cs) !Mix down by fc1 ! Filter, square, then FFT to get refined carrier frequency fc2. call four2a(cs,NZ,1,-1,1) !To freq domain ia=nint(0.75*baud/df) cs(ia:NZ-1-ia)=0. !Save only freqs around fc1 ! do i=1,NZ/2 ! filt=1/(1+((i*df)**2/(0.50*baud)**2)**8) ! cs(i)=cs(i)*filt ! cs(NZ+1-i)=cs(NZ+1-i)*filt ! enddo call four2a(cs,NZ,1,1,1) !Back to time domain cs=cs/NZ cs=cs*cs !Square the data call four2a(cs,NZ,1,-1,1) !Compute squared spectrum ! Find two peaks separated by baud pmax=0. fc2=0. ! ja=nint(0.3*baud/df) ja=nint(0.5*baud/df) k=1 sp2=0.0 do j=-ja,ja f2=j*df ia=nint((f2-0.5*baud)/df) if(ia.lt.0) ia=ia+NZ ib=nint((f2+0.5*baud)/df) p=real(cs(ia))**2 + aimag(cs(ia))**2 + & real(cs(ib))**2 + aimag(cs(ib))**2 if(p.gt.pmax) then pmax=p fc2=0.5*f2 endif freqs(k)=0.5*f2 sp2(k)=p k=k+1 ! write(52,1200) f2,p,db(p) !1200 format(f10.3,2f15.3) enddo do i=1,npeaks pkloc=maxloc(sp2) ipk=pkloc(1) fpks(i)=freqs(ipk) ipk0=max(1,ipk-2) ipk1=min(413,ipk+2) ! ipk0=ipk ! ipk1=ipk sp2(ipk0:ipk1)=0.0 enddo return end subroutine getfc2