Make ft2d slightly more robust. Still very rough.

This commit is contained in:
Steve Franke 2019-01-13 10:58:35 -06:00
parent 8f1baae048
commit 1fb89929a9
2 changed files with 19 additions and 14 deletions

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@ -98,12 +98,11 @@ fsum2=0.0
close(10) close(10)
call getcandidates2(iwave,100.0,3000.0,0.2,2200.0,100,savg,candidates,ncand,sbase) call getcandidates2(iwave,100.0,3000.0,0.2,2200.0,100,savg,candidates,ncand,sbase)
ndecodes=0 ndecodes=0
ncand=1
do icand=1,ncand do icand=1,ncand
f0=candidates(icand,1) f0=candidates(icand,1)
xsnr=1.0 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 call ft2_downsample(iwave,f0,c2) ! downsample from 160s/Symbol to 10s/Symbol
ibest=-1 ibest=-1
sybest=-99. sybest=-99.
@ -137,13 +136,12 @@ call twkfreq1(c2,NMAX/16,fs,a,cb)
enddo enddo
freq=f0+dfbest freq=f0+dfbest
fsum=fsum+freq fsum=fsum+freq
fsum2=fsum+freq*freq fsum2=fsum2+freq*freq
a=0. a=0.
a(1)=-dfbest a(1)=-dfbest
!write(*,*) 'dfbest ',dfbest
!dfbest=0.0 !dfbest=0.0
!ibest=187 !ibest=187
call twkfreq1(c2,NMAX/16,fs,a,cb) call twkfreq1(c2,NMAX/16,fs,a,cb)
ib=ibest ib=ibest
cd=cb(ib:ib+144*10-1) cd=cb(ib:ib+144*10-1)
s2=sum(cd*conjg(cd))/(10*144) s2=sum(cd*conjg(cd))/(10*144)
@ -198,6 +196,8 @@ call twkfreq1(c2,NMAX/16,fs,a,cb)
sbits=sbits3 sbits=sbits3
hbits=hbits3 hbits=hbits3
endif endif
nsync_qual=count(hbits(1:16).eq.s16)
if(nsync_qual.lt.12) cycle
rxdata=sbits(17:144) rxdata=sbits(17:144)
rxav=sum(rxdata(1:128))/128.0 rxav=sum(rxdata(1:128))/128.0
rx2av=sum(rxdata(1:128)*rxdata(1:128))/128.0 rx2av=sum(rxdata(1:128)*rxdata(1:128))/128.0
@ -239,9 +239,9 @@ call twkfreq1(c2,NMAX/16,fs,a,cb)
write(*,1120) write(*,1120)
1120 format("<DecodeFinished>") 1120 format("<DecodeFinished>")
favg=fsum/1000.0 favg=fsum/100.0
fstd=sqrt(fsum2/1000.0-favg*favg) fstd=sqrt(fsum2/100.0-favg*favg)
write(*,*) "Mean, std frequency: ",favg,fstd !write(*,*) "Mean, std frequency: ",favg,fstd
999 end program ft2d 999 end program ft2d
subroutine getbitmetric(ib,ps,ns,xmet) subroutine getbitmetric(ib,ps,ns,xmet)
@ -294,14 +294,19 @@ subroutine ft2_downsample(iwave,f0,c)
real x(NMAX) real x(NMAX)
equivalence (x,cx) equivalence (x,cx)
BW=4.0*75
df=12000.0/NMAX df=12000.0/NMAX
x=iwave x=iwave
call four2a(x,NMAX,1,-1,0) !r2c FFT to freq domain call four2a(x,NMAX,1,-1,0) !r2c FFT to freq domain
ibw=nint(BW/df)
i0=nint(f0/df) i0=nint(f0/df)
c1=0.
c1(0)=cx(i0) c1(0)=cx(i0)
do i=1,NFFT2/2 do i=1,NFFT2/2
c1(i)=cx(i0+i) arg=(i-1)*df/bw
c1(NFFT2-i)=cx(i0-i) win=exp(-arg*arg)
c1(i)=cx(i0+i)*win
c1(NFFT2-i)=cx(i0-i)*win
enddo enddo
c1=c1/NFFT2 c1=c1/NFFT2
call four2a(c1,NFFT2,1,1,1) !c2c FFT back to time domain call four2a(c1,NFFT2,1,1,1) !c2c FFT back to time domain

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@ -44,8 +44,8 @@ subroutine getcandidates2(id,nfa,nfb,syncmin,nfqso,maxcand,savg,candidate, &
imax=i imax=i
endif endif
enddo enddo
f0=imax*df
ncand=1 ncand=1
candidate(1,1)=imax*df candidate(1,1)=f0
return return
end subroutine getcandidates2 end subroutine getcandidates2