WSJT-X/lib/fsk4hf/wspr5d_exp.f90
2018-06-04 08:04:22 -05:00

571 lines
16 KiB
Fortran

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,zzsum
complex cc(110) !Complex correlation coefficients
complex*8 cfac
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)
logical reset
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,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
npeaks=5
call getfc2(c400,npeaks,fs400,fc1,fpks) !Refined freq
! do idf=1,npeaks ! consider the top npeak peaks
do idf=1,1 ! for genie-aided sync
fc1=125.0 ! genie provided
fc2=0.0 ! from the genie
! fc2=fpks(idf)
call downsample(c400,fc1+fc2,cd)
s2=sum(cd*conjg(cd))/(16*412)
cd=cd/sqrt(s2)
do is=0,0 ! dt search range is zeroed for genie-aided sync
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)
zzsum=0.0
do iseq=1,4,3
if(iseq.eq.4) then
k=1-2*3
nseq=9
istep=3*4
else
k=1-2*iseq
nseq=iseq*3
istep=iseq*4
endif
icc=1
do i=1,408,istep
j=(i+1)*16
if(iseq.eq.4) then
! phase=-1.18596900
! For now, average complex corr. coeffs over the entire frame to
! estimate phase
phase=atan2(imag(zzsum),real(zzsum))
k=k+3*2
call mskcohdet(nseq,ca(j),pp,id(k),softbits,phase)
else
k=k+iseq*2
call mskseqdet(nseq,ca(j),pp,id(k),softbits,1,zz)
cc(icc)=zz
write(32,*) icc,real(cc(icc)),imag(cc(icc))
icc=icc+1
zzsum=zzsum+zz
endif
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 .ge. 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
cm=0.0
do idel=-200,200
df=idel*0.001
! dpha=twopi*df*12.0*(16/22.0)
dpha=twopi*df*4.0*(16/22.0)
phase=0.0
zzsum=0.0
do i=1,102
cfac=cmplx(cos(phase),sin(phase))
zzsum=zzsum+cc(i)*cfac
phase=mod(phase+dpha,twopi)
enddo
if(abs(zzsum).gt.cm) then
cm=abs(zzsum)
dfbest=df
endif
! write(*,*) df,abs(zzsum)
enddo
write(*,*) 'dfbest ',dfbest
write(*,*) 'final estimated frequency is: ',fc1+fc2+dfbest
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=1.20
llr=2*rxdata/(sigma*sigma)
apmask=0
max_iterations=40
ifer=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
nhardmin=0
if(niterations.lt.0) call osd300(llr,apmask,5,decoded,cw,nhardmin,dmin)
if(nhardmin.gt.0) niterations=nhardmin
nbadcrc=0
call chkcrc10(decoded,nbadcrc)
if(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)
freq=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,iseq,niterations
!1212 format(a4,i4,f5.1,f11.6,i3,2x,a22,a1,i3,i3,i3,i4)
1212 format(a4,i4,f8.3,f8.3,i3,2x,a22,a1,i3,i3,i3,i3,i4)
goto 888
endif
enddo !iseq
enddo
enddo
888 continue
enddo
write(*,1120)
1120 format("<DecodeFinished>")
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,zz)
!
! 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.0 ) 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(1:64*ns/3)*conjg(cbest(1:64*ns/3)))/1.e3
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 mskcohdet(ns,cdat,pp,bsync,softbits,phase)
!
! Coherent demodulate blocks of 9 bits (ns).
!
complex cdat(16*12),crot(16*12)
real pp(32),softbits(9)
np=2**ns-1
softbits=0.0
crot=cdat*cmplx(cos(phase),-sin(phase))
softbits(1)=sum(imag(crot(1:32)*pp))
softbits(2)=sum(real(crot(17:48)*pp))
softbits(3)=sum(imag(crot(33:64)*pp))
softbits(4)=sum(imag(crot(65:96)*pp))
softbits(5)=sum(real(crot(81:112)*pp))
softbits(6)=sum(imag(crot(97:128)*pp))
softbits(7)=sum(imag(crot(129:160)*pp))
softbits(8)=sum(real(crot(145:176)*pp))
softbits(9)=sum(imag(crot(161:192)*pp))
softbits=softbits/64.
end subroutine mskcohdet
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 !optimized for sequence detection
b=6.0
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