From 2517106629294d9e34249f62e9210e888c6000b7 Mon Sep 17 00:00:00 2001 From: Steven Franke Date: Sun, 21 May 2017 22:19:57 +0000 Subject: [PATCH] Add an experimental decoder for wspr5. git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@7695 ab8295b8-cf94-4d9e-aec4-7959e3be5d79 --- lib/fsk4hf/wspr5d_exp.f90 | 275 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 275 insertions(+) create mode 100644 lib/fsk4hf/wspr5d_exp.f90 diff --git a/lib/fsk4hf/wspr5d_exp.f90 b/lib/fsk4hf/wspr5d_exp.f90 new file mode 100644 index 000000000..80b093b7f --- /dev/null +++ b/lib/fsk4hf/wspr5d_exp.f90 @@ -0,0 +1,275 @@ +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 + 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=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 + +! ebits=hbits(1:411) +! isum=sum(id(1:205)*(2*ebits(1:409:2)-1))/2 +!write(*,*) is,isum + 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 +!write(*,'(f10.3)') fbest +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