In principle, ft2d can now decode multiple signals. Not yet tested.

This commit is contained in:
Steve Franke 2019-01-13 15:44:16 -06:00
parent 1fb89929a9
commit 348e7c8ad5
2 changed files with 56 additions and 62 deletions

View File

@ -54,7 +54,7 @@ program ft2d
cc0=cmplx(cos(the),sin(the))
nargs=iargc()
if(nargs.lt.1) then
print*,'Usage: ft2d [-a <data_dir>] [-f fMHz] [-c ncoh] file1 [file2 ...]'
print*,'Usage: ft2d [-a <data_dir>] [-f fMHz] file1 [file2 ...]'
go to 999
endif
iarg=1
@ -71,23 +71,7 @@ program ft2d
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
xs1=0.0
xs2=0.0
fr1=0.0
fr2=0.0
nav=0
ngood=0
fsum=0.0
fsum2=0.0
do ifile=iarg,nargs
call getarg(ifile,infile)
j2=index(infile,'.wav')
@ -96,57 +80,56 @@ fsum2=0.0
read(infile(j2-4:j2-1),*) nutc
datetime=infile(j2-11:j2-1)
close(10)
call getcandidates2(iwave,100.0,3000.0,0.2,2200.0,100,savg,candidates,ncand,sbase)
candidates=0.0
ncand=0
call getcandidates2(iwave,375.0,3000.0,0.2,2200.0,100,savg,candidates,ncand,sbase)
ndecodes=0
do icand=1,ncand
f0=candidates(icand,1)
xsnr=1.0
if( f0.le.375.0 .or. f0.ge.(5000.0-375.0) ) cycle
call ft2_downsample(iwave,f0,c2) ! downsample from 160s/Symbol to 10s/Symbol
ibest=-1
sybest=-99.
dfbest=-1.
do if=-15,+15
df=if
a=0.
a(1)=-df
call twkfreq1(c2,NMAX/16,fs,a,cb)
! 750 samples/second here
do is=0,374
csync1=0.
cterm=1
do ib=1,16
i1=(ib-1)*10+is
i2=i1+136*10
if(s16(ib).eq.1) then
csync1=csync1+sum(cb(i1:i1+9)*conjg(c1(0:9)))*cterm
cterm=cterm*cc1
else
csync1=csync1+sum(cb(i1:i1+9)*conjg(c0(0:9)))*cterm
cterm=cterm*cc0
ibest=-1
sybest=-99.
dfbest=-1.
do if=-15,+15
df=if
a=0.
a(1)=-df
call twkfreq1(c2,NMAX/16,fs,a,cb)
do is=0,374
csync1=0.
cterm=1
do ib=1,16
i1=(ib-1)*10+is
i2=i1+136*10
if(s16(ib).eq.1) then
csync1=csync1+sum(cb(i1:i1+9)*conjg(c1(0:9)))*cterm
cterm=cterm*cc1
else
csync1=csync1+sum(cb(i1:i1+9)*conjg(c0(0:9)))*cterm
cterm=cterm*cc0
endif
enddo
if(abs(csync1).gt.sybest) then
ibest=is
sybest=abs(csync1)
dfbest=df
endif
enddo
if(abs(csync1).gt.sybest) then
ibest=is
sybest=abs(csync1)
dfbest=df
endif
enddo
enddo
freq=f0+dfbest
fsum=fsum+freq
fsum2=fsum2+freq*freq
a=0.
a(1)=-dfbest
!dfbest=0.0
!ibest=187
a=0.
a(1)=-dfbest
call twkfreq1(c2,NMAX/16,fs,a,cb)
ib=ibest
cd=cb(ib:ib+144*10-1)
s2=sum(cd*conjg(cd))/(10*144)
cd=cd/sqrt(s2)
do nseq=1,4
do nseq=1,5
if( nseq.eq.1 ) then ! noncoherent single-symbol detection
sbits1=0.0
do ibit=1,144
@ -197,7 +180,7 @@ fsum2=fsum2+freq*freq
hbits=hbits3
endif
nsync_qual=count(hbits(1:16).eq.s16)
if(nsync_qual.lt.12) cycle
if(nsync_qual.lt.10) exit
rxdata=sbits(17:144)
rxav=sum(rxdata(1:128))/128.0
rx2av=sum(rxdata(1:128)*rxdata(1:128))/128.0
@ -227,21 +210,20 @@ fsum2=fsum2+freq*freq
ndecodes=ndecodes+1
decodes(ndecodes)=message
nsnr=nint(xsnr)
freq=f0+dfbest
1210 format(a11,2i4,f6.2,f12.7,2x,a22,i3)
write(*,1212) datetime(8:11),nsnr,ibest/750.0,freq,message,'*',idf,nseq,ijitter,nharderror,nhardmin
1212 format(a4,i4,f5.1,f11.1,2x,a22,a1,i5,i5,i5,i5,i5)
goto 888
endif
enddo ! nseq
888 continue
888 continue
enddo !candidate list
enddo !files
write(*,1120)
1120 format("<DecodeFinished>")
favg=fsum/100.0
fstd=sqrt(fsum2/100.0-favg*favg)
!write(*,*) "Mean, std frequency: ",favg,fstd
999 end program ft2d
subroutine getbitmetric(ib,ps,ns,xmet)

View File

@ -1,4 +1,4 @@
subroutine getcandidates2(id,nfa,nfb,syncmin,nfqso,maxcand,savg,candidate, &
subroutine getcandidates2(id,fa,fb,syncmin,nfqso,maxcand,savg,candidate, &
ncand,sbase)
! For now, hardwired to find the largest peak in the average spectrum
@ -12,6 +12,7 @@ subroutine getcandidates2(id,nfa,nfb,syncmin,nfqso,maxcand,savg,candidate, &
real candidate(3,maxcand)
integer*2 id(NMAX)
integer*1 s8(8)
integer indx(NH1)
data s8/0,1,1,1,0,0,1,0/
equivalence (x,cx)
@ -36,16 +37,27 @@ subroutine getcandidates2(id,nfa,nfb,syncmin,nfqso,maxcand,savg,candidate, &
savsm(i)=sum(savg(i-1:i+1))/3.
enddo
nfa=fa/df
nfb=fb/df
np=nfb-nfa+1
indx=0
call indexx(savsm(nfa:nfb),np,indx)
xn=savsm(nfa+indx(nint(0.3*np)))
savsm=savsm/xn
imax=-1
xmax=-99.
do i=2,NH1-1
if(savsm(i).gt.savsm(i-1).and.savsm(i).gt.savsm(i+1).and.savsm(i).gt.xmax) then
if(savsm(i).gt.savsm(i-1).and. &
savsm(i).gt.savsm(i+1).and. &
savsm(i).gt.xmax) then
xmax=savsm(i)
imax=i
endif
enddo
f0=imax*df
ncand=1
candidate(1,1)=f0
if(xmax.gt.1.2) then
ncand=ncand+1
candidate(1,ncand)=f0
endif
return
end subroutine getcandidates2