218 lines
6.5 KiB
Plaintext
218 lines
6.5 KiB
Plaintext
|
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.
|
||
|
|
|
||
|
|
! Reception and Demodulation algorithm:
|
||
|
|
! 1. Compute coarse spectrum; find fc1 = approx carrier freq
|
||
|
|
! 2. Mix from fc1 to 0; LPF at +/- 0.75*R
|
||
|
|
! 3. Square, FFT; find peaks near -R/2 and +R/2 to get fc2
|
||
|
|
! 4. Mix from fc2 to 0
|
||
|
|
! 5. Fit cb13 (central part of csync) to c -> lag, phase
|
||
|
|
! 6. Fit complex ploynomial for channel equalization
|
||
|
|
! 7. Get soft bits from equalized data
|
||
|
|
|
||
|
|
! 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 c1(0:NZ-1) !Complex waveform
|
||
|
|
complex zz(NS+ND) !Complex symbol values (intermediate)
|
||
|
|
complex z
|
||
|
|
real*8 fMHz
|
||
|
|
real rxdata(ND),llr(ND) !Soft symbols
|
||
|
|
real pp(2*NSPS) !Shaped pulse for OQPSK
|
||
|
|
real a(5) !For twkfreq1
|
||
|
|
real aa(20),bb(20) !Fitted polyco's
|
||
|
|
real fpks(20)
|
||
|
|
integer id(NS+ND) !NRZ values (+/-1) for Sync and Data
|
||
|
|
integer ierror(NS+ND)
|
||
|
|
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)
|
||
|
|
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,N2 !Half-sine pulse shape
|
||
|
|
pp(i)=sin(0.5*(i-1)*twopi/(2*NSPS))
|
||
|
|
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=150.0
|
||
|
|
call getfc1w(c,fs,fa,fb,fc1,xsnr) !First approx for freq
|
||
|
|
npeaks=20
|
||
|
|
call getfc2w(c,csync,npeaks,fs,fc1,fpks) !Refined freq
|
||
|
|
|
||
|
|
a(1)=-fc1
|
||
|
|
a(2:5)=0.
|
||
|
|
call twkfreq1(c,NZ,fs,a,c) !Mix c down by fc1+fc2
|
||
|
|
|
||
|
|
! Find time offset xdt
|
||
|
|
amax=0.
|
||
|
|
jpk=0
|
||
|
|
iaa=0
|
||
|
|
ibb=NZ-1
|
||
|
|
jmax=1260
|
||
|
|
do j=-jmax,jmax,NSPS/8
|
||
|
|
ia=j
|
||
|
|
ib=NZ-1+j
|
||
|
|
if(ia.lt.0) then
|
||
|
|
ia=0
|
||
|
|
iaa=-j
|
||
|
|
else
|
||
|
|
iaa=0
|
||
|
|
endif
|
||
|
|
if(ib.gt.NZ-1) then
|
||
|
|
ib=NZ-1
|
||
|
|
ibb=NZ-1-j
|
||
|
|
endif
|
||
|
|
z=sum(c(ia:ib)*conjg(csync(iaa:ibb)))
|
||
|
|
write(51,*) j/fs,real(z),imag(z)
|
||
|
|
if(abs(z).gt.amax) then
|
||
|
|
amax=abs(z)
|
||
|
|
jpk=j
|
||
|
|
endif
|
||
|
|
enddo
|
||
|
|
xdt=jpk/fs
|
||
|
|
xdt=1.0
|
||
|
|
jpk=fs*xdt
|
||
|
|
do i=0,NZ-1
|
||
|
|
j=i+jpk
|
||
|
|
if(j.ge.0 .and. j.lt.NZ) c1(i)=c(j)
|
||
|
|
enddo
|
||
|
|
|
||
|
|
nterms=maxn
|
||
|
|
do itry=1,npeaks
|
||
|
|
nhard0=0
|
||
|
|
nhardsync0=0
|
||
|
|
ifer=1
|
||
|
|
a(1)=-fpks(itry)
|
||
|
|
a(2:5)=0.
|
||
|
|
call twkfreq1(c1,NZ,fs,a,c) !Mix c1 into c
|
||
|
|
call cpolyfitw(c,pp,id,maxn,aa,bb,zz,nhs)
|
||
|
|
call msksoftsymw(zz,aa,bb,id,nterms,ierror,rxdata,nhard0,nhardsync0)
|
||
|
|
if(nhardsync0.gt.35) cycle
|
||
|
|
rxav=sum(rxdata)/ND
|
||
|
|
rx2av=sum(rxdata*rxdata)/ND
|
||
|
|
rxsig=sqrt(rx2av-rxav*rxav)
|
||
|
|
rxdata=rxdata/rxsig
|
||
|
|
ss=0.84
|
||
|
|
llr=2.0*rxdata/(ss*ss)
|
||
|
|
apmask=0
|
||
|
|
max_iterations=40
|
||
|
|
ifer=0
|
||
|
|
call bpdecode300(llr,apmask,max_iterations,decoded,niterations,cw)
|
||
|
|
if(niterations.lt.0) call osd300(llr,4,decoded,niterations,cw)
|
||
|
|
nbadcrc=0
|
||
|
|
if(niterations.ge.0) call chkcrc10(decoded,nbadcrc)
|
||
|
|
if(niterations.lt.0 .or. nbadcrc.ne.0) ifer=1
|
||
|
|
if(ifer.eq.0) exit
|
||
|
|
enddo !Freq dither loop
|
||
|
|
message=' '
|
||
|
|
if(ifer.eq.0) then
|
||
|
|
write(cbits,1100) decoded(1:50)
|
||
|
|
1100 format(50i1)
|
||
|
|
read(cbits,1102) idat
|
||
|
|
1102 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=fMHz + 1.d-6*(fc1+fpks(itry))
|
||
|
|
nfdot=0
|
||
|
|
write(13,1110) datetime,0,nsnr,xdt,freq,message,nfdot
|
||
|
|
1110 format(a11,2i4,f6.2,f12.7,2x,a22,i3)
|
||
|
|
write(*,1112) datetime(8:11),nsnr,xdt,freq,nfdot,message,itry
|
||
|
|
1112 format(a4,i4,f5.1,f11.6,i3,2x,a22,i4)
|
||
|
|
endif
|
||
|
|
enddo ! ifile loop
|
||
|
|
write(*,1120)
|
||
|
|
1120 format("<DecodeFinished>")
|
||
|
|
|
||
|
|
999 end program wspr5d
|