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
This commit is contained in:
Steven Franke 2017-05-21 22:19:57 +00:00
parent bddcc32de0
commit 2517106629

275
lib/fsk4hf/wspr5d_exp.f90 Normal file
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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 <data_dir>] [-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("<DecodeFinished>")
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