WSJT-X/lib/fsk4hf/wsprcpmd.f90
Steven Franke 1f9d73963b Update wsprcpm simulator and decoder.
git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@8603 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
2018-04-03 14:55:55 +00:00

551 lines
15 KiB
Fortran

program wsprcpmd
! Decode WSPRCPM data read from *.c2 or *.wav files.
! WSPRCPM is a WSPR-like mode based on full-response CPM.
!
! Currently configured to use (204,68) r=1/3 LDPC code, regular column weight 3.
! 50 data bits + 14 bit CRC + 4 "0" bits. The 4 "0" bits are unused bits that
! are not transmitted. At the decoder, these bits are treated as "AP" bits.
! This shortens the code to (200,64) r=0.32, slightly decreasing the code rate.
!
! Frame format is:
! d100 p32 d100 (232) channel symbols
!
use crc
include 'wsprcpm_params.f90'
parameter(NMAX=120*12000)
character arg*8,message*22,cbits*50,infile*80,fname*16,datetime*11
character*22 decodes(100)
character*120 data_dir
character*32 uwbits
character*68 dmsg
complex c2(0:120*12000/32-1) !Complex waveform
complex cframe(0:216*200-1) !Complex waveform
complex cd(0:216*10-1) !Complex waveform
complex c1(0:9,0:1),c0(0:9,0:1)
complex ccor(0:1,216)
complex csum,cterm
real*8 fMHz
real rxdata(ND),llr(204) !Soft symbols
real sbits(216),sbits1(216),sbits3(216)
real ps(0:8191),psbest(0:8191)
real candidates(100,2)
integer iuniqueword0
integer isync(200) !Unique word
integer isync2(216)
integer ipreamble(16) !Preamble vector
integer ihdr(11)
integer*2 iwave(NMAX) !Generated full-length waveform
integer*1,target :: idat(9)
integer*1 decoded(68),apmask(204),cw(204)
integer*1 hbits(216),hbits1(216),hbits3(216)
data ipreamble/1,1,1,1,0,0,0,0,0,0,0,0,1,1,1,1/
data iuniqueword0/z'30C9E8AD'/
write(uwbits,'(b32.32)') iuniqueword0
read(uwbits,'(32i1)') isync(1:32)
read(uwbits,'(32i1)') isync(33:64)
read(uwbits,'(32i1)') isync(65:96)
read(uwbits,'(32i1)') isync(97:128)
read(uwbits,'(32i1)') isync(129:160)
read(uwbits,'(32i1)') isync(161:192)
read(uwbits,'(8i1)') isync(193:200)
fs=12000.0/NDOWN !Sample rate
dt=1.0/fs !Sample interval (s)
tt=NSPS*dt !Duration of "itone" symbols (s)
baud=1.0/tt !Keying rate for "itone" symbols (baud)
txt=NZ*dt !Transmission length (s)
h=1.00 !h=0.8 seems to be optimum for AWGN sensitivity (not for fading)
twopi=8.0*atan(1.0)
isync2(1:100)=isync(1:100)
isync2(101:104)=0 ! This is *not* backwards.
isync2(105:112)=1
isync2(113:116)=0
isync2(117:216)=isync(101:200)
! data sync tone
! 0 0 0
! 0 1 1
! 1 0 2
! 1 1 3
dphi=twopi*baud*(h/2.0)*dt*20 ! dt*10 is samp interval after downsample
do j=0,1
if(j.eq.0) then
dphi0=-3*dphi
dphi1=+1*dphi
else
dphi0=-1*dphi
dphi1=+3*dphi
endif
phi0=0.0
phi1=0.0
do i=0,9
c1(i,j)=cmplx(cos(phi1),sin(phi1))
c0(i,j)=cmplx(cos(phi0),sin(phi0))
phi1=mod(phi1+dphi1,twopi)
phi0=mod(phi0+dphi0,twopi)
enddo
enddo
nargs=iargc()
if(nargs.lt.1) then
print*,'Usage: wsprcpmd [-a <data_dir>] [-f fMHz] [-c ncoh] 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
ncoh=1
npdi=16
if(arg(1:2).eq.'-c') then
call getarg(iarg+1,arg)
read(arg,*) ncoh
iarg=iarg+2
npdi=16/ncoh
endif
! write(*,*) 'ncoh: ',ncoh,' npdi: ',npdi
open(13,file=trim(data_dir)//'/ALL_WSPR.TXT',status='unknown', &
position='append')
xs1=0.0
xs2=0.0
fr1=0.0
fr2=0.0
nav=0
ngood=0
do ifile=iarg,nargs
call getarg(ifile,infile)
open(10,file=infile,status='old',access='stream')
j1=index(infile,'.c2')
j2=index(infile,'.wav')
if(j1.gt.0) then
read(10,end=999) fname,ntrmin,fMHz,c2
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 wsprcpm_downsample(iwave,c2)
else
print*,'Wrong file format?'
go to 999
endif
close(10)
fa=-100.0
fb=100.0
fs=12000.0/32.0
npts=120*12000.0/32.0
nsync=16
call getcandidate2(c2,npts,fs,fa,fb,ncand,candidates) !First approx for freq
ndecodes=0
do icand=1,ncand
fc0=candidates(icand,1)
xsnr=candidates(icand,2)
xmax=-1e32
do i=-5,5
ft=fc0+i*0.2
call noncoherent_frame_sync(c2,ft,isync2,is,xf1)
if(xf1.gt.xmax) then
xmax=xf1
fc1=ft
is0=is
endif
enddo
call coherent_preamble_fsync(c2,ipreamble,nsync,NSPS,is0,fc1,fcest,xp1)
call noncoherent_frame_sync(c2,fcest,isync2,istart,xf2)
write(*,'(i5,i5,i5,4(f11.5,2x))') ifile,iii,istart,fc0,fc1,fcest
do ijitter=0,4
io=-10*(ijitter/2+1)
if(mod(ijitter,2).eq.0) io=10*(ijitter/2)
ib=max(0,istart+io)
cframe=c2(ib:ib+216*200-1)
call downsample2(cframe,fcest,cd)
s2=sum(cd*conjg(cd))/(10*216)
cd=cd/sqrt(s2)
do nseq=1,7
if( nseq.eq.1 ) then ! noncoherent single-symbol detection
sbits1=0.0
do ibit=1,216
j=isync2(ibit)
ib=(ibit-1)*10
ccor(1,ibit)=sum(cd(ib:ib+9)*conjg(c1(0:9,j)))
ccor(0,ibit)=sum(cd(ib:ib+9)*conjg(c0(0:9,j)))
sbits1(ibit)=abs(ccor(1,ibit))-abs(ccor(0,ibit))
hbits1(ibit)=0
if(sbits1(ibit).gt.0) hbits1(ibit)=1
enddo
sbits=sbits1
hbits=hbits1
sbits3=sbits1
hbits3=hbits1
elseif( nseq.ge.2 ) then
ps=0
if( nseq.eq. 2 ) nbit=3
if( nseq.eq. 3 ) nbit=5
if( nseq.eq. 4 ) nbit=7
if( nseq.eq. 5 ) nbit=9
if( nseq.eq. 6 ) nbit=11
if( nseq.eq. 7 ) nbit=13
numseq=2**(nbit)
do ibit=nbit/2+1,216-nbit/2
ps=0.0
pmax=0.0
do iseq=0,numseq-1
csum=0.0
cterm=1.0
k=1
do i=nbit-1,0,-1
ibb=iand(iseq/(2**i),1)
csum=csum+ccor(ibb,ibit-(nbit/2+1)+k)*cterm
cterm=-cterm
k=k+1
enddo
ps(iseq)=abs(csum)
if( ps(iseq) .gt. pmax ) then
pmax=ps(iseq)
ibflag=1
endif
enddo
if( ibflag .eq. 1 ) then
psbest=ps
ibflag=0
endif
call getmetric2(2**(nbit/2),psbest,numseq,sbits3(ibit))
hbits3(ibit)=0
if(sbits3(ibit).gt.0) hbits3(ibit)=1
enddo
sbits=sbits3
hbits=hbits3
endif
rxdata(1:100)=sbits(1:100)
rxdata(101:200)=sbits(117:216);
rxav=sum(rxdata(1:200))/200.0
rx2av=sum(rxdata(1:200)*rxdata(1:200))/200.0
rxsig=sqrt(rx2av-rxav*rxav)
rxdata=rxdata/rxsig
sigma=0.90
llr(201:204)=-5.0
llr(1:200)=2*rxdata/(sigma*sigma)
apmask=0
apmask(201:204)=1
max_iterations=40
ifer=0
call bpdecode204(llr,apmask,max_iterations,decoded,cw,nharderror,niterations)
nhardmin=-1
if(nharderror.lt.0) call osd204(llr,apmask,5,decoded,cw,nhardmin,dmin)
if(sum(decoded).eq.0) cycle
if(nhardmin.ge.0 .or. nharderror.ge.0) then
idat=0
write(dmsg,'(68i1)') decoded
read(dmsg(1:50),'(6b8.8,b2.2)') idat(1:7)
idat(7)=idat(7)*64
read(dmsg(51:64),'(b14.14)') ndec_crc
ncalc_crc=iand(crc14(c_loc(idat),9),z'FFFF')
nbadcrc=1
if(ncalc_crc .eq. ndec_crc) nbadcrc=0
else
cycle
endif
if( nbadcrc.eq.0 ) then
write(cbits,1200) decoded(1:50)
1200 format(50i1)
read(cbits,1202) idat
1202 format(8b8,b4)
idat(7)=ishft(idat(7),6)
call wqdecode(idat,message,itype)
idupe=0
do i=1,ndecodes
if(decodes(i).eq.message) idupe=1
enddo
if(idupe.eq.1) goto 888
ndecodes=ndecodes+1
decodes(ndecodes)=message
nsnr=nint(xsnr)
freq=fMHz + 1.d-6*(fc1+fbest)
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,ijitter,nharderror,nhardmin
1212 format(a4,i4,f5.1,f11.6,i3,2x,a22,a1,i5,i5,i5,i5,i5)
goto 888
endif
enddo ! nseq
enddo !jitter
888 continue
enddo !candidate list
enddo !files
write(*,1120)
1120 format("<DecodeFinished>")
999 end program wsprcpmd
subroutine coherent_preamble_fsync(c2,ipreamble,nsync,nsps,istart,fc0,fc1,xmax)
complex c2(0:120*12000/32-1)
complex cpreamble(0:16*200-1)
complex ctmp1(0:4*16*200-1)
complex ctwkp(0:16*200-1)
complex ccohp(0:15)
integer ipreamble(nsync)
logical first/.true./
save dt,first,h,twopi,cpreamble
if(first) then
baud=12000.0/6400.0
dt=32.0/12000.0
h=1.00
twopi=8.0*atan(1.0)
k=0
phi=0.0
dphi=twopi*baud*0.5*h*dt
do i=1,16
dp=dphi
if(ipreamble(i).eq.0) dp=-dphi
do j=1,200
cpreamble(k)=cmplx(cos(phi),sin(phi))
phi=mod(phi+dp,twopi)
k=k+1
enddo
enddo
first=.false.
endif
dphi=twopi*fc0*dt
ctwkp=cmplx(0.0,0.0)
phi=0
do i=0,nsync*nsps-1
ctwkp(i)=cpreamble(i)*cmplx(cos(phi),sin(phi))
phi=mod(phi+dphi,twopi)
enddo
ipstart=istart+100*200
ctmp1=0.0
ctmp1(0:16*200-1)=c2(ipstart:ipstart+16*200-1)*conjg(ctwkp)
call four2a(ctmp1,4*16*200,1,-1,1) !c2c FFT to freq domain
xmax=0.0
ctmp1=cshift(ctmp1,-200)
dfp=1/(4*6400.0/12000.0*16)
do i=150,250
xa=abs(ctmp1(i))
if(xa.gt.xmax) then
ishift=i
xmax=xa
endif
enddo
delta=(ishift-200)*dfp
xm1=abs(ctmp1(ishift-1))
x0=abs(ctmp1(ishift))
xp1=abs(ctmp1(ishift+1))
xint=(log(xm1)-log(xp1))/(log(xm1)+log(xp1)-2*log(x0))
delta2=delta+xint*dfp/2.0
fc1=fc0+delta2
return
end subroutine coherent_preamble_fsync
subroutine noncoherent_frame_sync(c2,fc,isync2,istart,ssmax)
complex c2(0:120*12000/32-1)
complex ct0(0:199),ct1(0:199),ct2(0:199),ct3(0:199)
integer isync2(216)
twopi=8.0*atan(1.0)
h=1.0
dt=32.0/12000.0
baud=12000.0/6400.0
imax=370 ! defines dt search range (375 samples/s)
ssmax=-1e32
izero=375
do it = -imax,imax,10
! noncoherent wspr-type dt estimation
dp0=twopi*(fc-1.5*h*baud)*dt
dp1=twopi*(fc-0.5*h*baud)*dt
dp2=twopi*(fc+0.5*h*baud)*dt
dp3=twopi*(fc+1.5*h*baud)*dt
th0=0.0
th1=0.0
th2=0.0
th3=0.0
do i=0,199
ct0(i)=cmplx(cos(th0),sin(th0))
ct1(i)=cmplx(cos(th1),sin(th1))
ct2(i)=cmplx(cos(th2),sin(th2))
ct3(i)=cmplx(cos(th3),sin(th3))
th0=mod(th0+dp0,twopi)
th1=mod(th1+dp1,twopi)
th2=mod(th2+dp2,twopi)
th3=mod(th3+dp3,twopi)
enddo
ss=0.0
totp=0.0
do is=1,216
i0=izero+it+(is-1)*200
p0=abs(sum(c2(i0:i0+199)*conjg(ct0)))
p1=abs(sum(c2(i0:i0+199)*conjg(ct1)))
p2=abs(sum(c2(i0:i0+199)*conjg(ct2)))
p3=abs(sum(c2(i0:i0+199)*conjg(ct3)))
p0=sqrt(p0)
p1=sqrt(p1)
p2=sqrt(p2)
p3=sqrt(p3)
totp=totp+p0+p1+p2+p3
! cmet=(p1+p3)-(p0+p2)
cmet=max(p1,p3)-max(p0,p2) ! This works better near threshold SNR
if(isync2(is).eq.0) ss=ss-cmet
if(isync2(is).eq.1) ss=ss+cmet
enddo
ss=ss/totp
if(ss.gt.ssmax) then
ioffset=it
ssmax=ss
endif
enddo
istart=izero+ioffset
return
end subroutine noncoherent_frame_sync
subroutine getmetric2(ib,ps,ns,xmet)
real ps(0:ns-1)
xm1=0
xm0=0
do i=0,ns-1
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 getmetric2
subroutine downsample2(ci,f0,co)
parameter(NI=216*200,NH=NI/2,NO=NI/20) ! downsample from 200 samples per symbol to 10
complex ci(0:NI-1),ct(0:NI-1)
complex co(0:NO-1)
fs=12000.0/32.0
df=fs/NI
ct=ci
call four2a(ct,NI,1,-1,1) !c2c FFT to freq domain
i0=nint(f0/df)
ct=cshift(ct,i0)
co=0.0
co(0)=ct(0)
b=8.0
do i=1,NO/2
arg=(i*df/b)**2
filt=exp(-arg)
co(i)=ct(i)*filt
co(NO-i)=ct(NI-i)*filt
enddo
co=co/NO
call four2a(co,NO,1,1,1) !c2c FFT back to time domain
return
end subroutine downsample2
subroutine getcandidate2(c,npts,fs,fa,fb,ncand,candidates)
parameter(NDAT=200,NFFT1=120*12000/32,NH1=NFFT1/2,NFFT2=120*12000/320,NH2=NFFT2/2)
complex c(0:npts-1) !Complex waveform
complex cc(0:NFFT1-1)
complex csfil(0:NFFT2-1)
complex cwork(0:NFFT2-1)
real bigspec(0:NFFT2-1)
complex c2(0:NFFT1-1) !Short spectra
real s(-NH1+1:NH1) !Coarse spectrum
real ss(-NH1+1:NH1) !Smoothed coarse spectrum
real candidates(100,2)
integer indx(NFFT2-1)
logical first
data first/.true./
save first,w,df,csfil
if(first) then
df=10*fs/NFFT1
csfil=cmplx(0.0,0.0)
do i=0,NFFT2-1
csfil(i)=exp(-((i-NH2)/20.0)**2)
enddo
csfil=cshift(csfil,NH2)
call four2a(csfil,NFFT2,1,-1,1)
first=.false.
endif
cc=cmplx(0.0,0.0)
cc(0:npts-1)=c;
call four2a(cc,NFFT1,1,-1,1)
cc=abs(cc)**2
call four2a(cc,NFFT1,1,-1,1)
cwork(0:NH2)=cc(0:NH2)*conjg(csfil(0:NH2))
cwork(NH2+1:NFFT2-1)=cc(NFFT1-NH2+1:NFFT1-1)*conjg(csfil(NH2+1:NFFT2-1))
call four2a(cwork,NFFT2,1,+1,1)
bigspec=cshift(real(cwork),-NH2)
il=NH2+fa/df
ih=NH2+fb/df
nnl=ih-il+1
call indexx(bigspec(il:il+nnl-1),nnl,indx)
xn=bigspec(il-1+indx(nint(0.3*nnl)))
bigspec=bigspec/xn
ncand=0
do i=il,ih
if((bigspec(i).gt.bigspec(i-1)).and. &
(bigspec(i).gt.bigspec(i+1)).and. &
(bigspec(i).gt.1.15).and.ncand.lt.100) then
ncand=ncand+1
candidates(ncand,1)=df*(i-NH2)
candidates(ncand,2)=10*log10(bigspec(i))-30.0
endif
enddo
! do i=1,ncand
! write(*,*) i,candidates(i,1),candidates(i,2)
! enddo
return
end subroutine getcandidate2
subroutine wsprcpm_downsample(iwave,c)
! Input: i*2 data in iwave() at sample rate 12000 Hz
! Output: Complex data in c(), sampled at 400 Hz
include 'wsprcpm_params.f90'
parameter (NMAX=120*12000,NFFT2=NMAX/32)
integer*2 iwave(NMAX)
complex c(0:NMAX/32-1)
complex c1(0:NFFT2-1)
complex cx(0:NMAX/2)
real x(NMAX)
equivalence (x,cx)
df=12000.0/NMAX
x=iwave
call four2a(x,NMAX,1,-1,0) !r2c FFT to freq domain
i0=nint(1500.0/df)
c1(0)=cx(i0)
do i=1,NFFT2/2
c1(i)=cx(i0+i)
c1(NFFT2-i)=cx(i0-i)
enddo
c1=c1/NFFT2
call four2a(c1,NFFT2,1,1,1) !c2c FFT back to time domain
c=c1(0:NMAX/32-1)
return
end subroutine wsprcpm_downsample