mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2024-11-18 10:01:57 -05:00
ab3832fa82
git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@7780 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
233 lines
5.5 KiB
Fortran
233 lines
5.5 KiB
Fortran
subroutine ft8b(dd0,newdat,nfqso,f1,xdt,nharderrors,dmin,nbadcrc,message,xsnr)
|
|
|
|
use timer_module, only: timer
|
|
include 'ft8_params.f90'
|
|
parameter(NRECENT=10,NP2=2812)
|
|
character message*22,msgsent*22
|
|
character*12 recent_calls(NRECENT)
|
|
real a(5)
|
|
real s1(0:7,ND),s2(0:7,NN)
|
|
real ps(0:7)
|
|
real rxdata(3*ND),llr(3*ND) !Soft symbols
|
|
real dd0(15*12000)
|
|
integer*1 decoded(KK),apmask(3*ND),cw(3*ND)
|
|
integer itone(NN)
|
|
integer icos7(0:6)
|
|
complex cd0(3125)
|
|
complex csync(0:6,32)
|
|
complex ctwk(32)
|
|
complex csymb(32)
|
|
logical newdat,first
|
|
data icos7/2,5,6,0,4,1,3/
|
|
data first/.true./
|
|
save first,twopi,fs2,dt2,taus,baud,csync
|
|
|
|
if( first ) then
|
|
twopi=8.0*atan(1.0)
|
|
fs2=12000.0/64.0
|
|
dt2=1/fs2
|
|
taus=32*dt2
|
|
baud=1/taus
|
|
do i=0,6
|
|
phi=0.0
|
|
dphi=twopi*icos7(i)*baud*dt2
|
|
do j=1,32
|
|
csync(i,j)=cmplx(cos(phi),sin(phi))
|
|
phi=mod(phi+dphi,twopi)
|
|
enddo
|
|
enddo
|
|
first=.false.
|
|
endif
|
|
|
|
max_iterations=40
|
|
norder=2
|
|
! if(abs(nfqso-f1).lt.10.0) norder=3
|
|
call timer('ft8_down',0)
|
|
call ft8_downsample(dd0,newdat,f1,cd0)
|
|
call timer('ft8_down',1)
|
|
|
|
i0=xdt*fs2
|
|
smax=0.0
|
|
do idt=i0-16,i0+16
|
|
sync=0
|
|
do i=0,6
|
|
i1=idt+i*32
|
|
i2=i1+36*32
|
|
i3=i1+72*32
|
|
term1=0.0 ! this needs to be fixed...
|
|
term2=0.0
|
|
term3=0.0
|
|
if( i1.ge.1 .and. i1+31.le.NP2 ) &
|
|
term1=abs(sum(cd0(i1:i1+31)*conjg(csync(i,1:32))))
|
|
if( i2.ge.1 .and. i2+31.le.NP2 ) &
|
|
term2=abs(sum(cd0(i2:i2+31)*conjg(csync(i,1:32))))
|
|
if( i3.ge.1 .and. i3+31.le.NP2 ) &
|
|
term3=abs(sum(cd0(i3:i3+31)*conjg(csync(i,1:32))))
|
|
sync=sync+term1+term2+term3
|
|
enddo
|
|
if( sync .gt. smax ) then
|
|
smax=sync
|
|
ibest=idt
|
|
endif
|
|
enddo
|
|
xdt2=ibest*dt2
|
|
|
|
! peak up the frequency
|
|
i0=xdt2*fs2
|
|
smax=0.0
|
|
do ifr=-5,5
|
|
delf=ifr*0.5
|
|
dphi=twopi*delf*dt2
|
|
phi=0.0
|
|
do i=1,32
|
|
ctwk(i)=cmplx(cos(phi),sin(phi))
|
|
phi=mod(phi+dphi,twopi)
|
|
enddo
|
|
sync=0.0
|
|
do i=0,6
|
|
i1=i0+i*32
|
|
i2=i1+36*32
|
|
i3=i1+72*32
|
|
term1=0.0 ! this needs to be fixed...
|
|
term2=0.0
|
|
term3=0.0
|
|
if( i1.ge.1 .and. i1+31.le.NP2 ) &
|
|
term1=abs(sum(cd0(i1:i1+31)*conjg(ctwk*csync(i,1:32))))
|
|
if( i2.ge.1 .and. i2+31.le.NP2 ) &
|
|
term2=abs(sum(cd0(i2:i2+31)*conjg(ctwk*csync(i,1:32))))
|
|
if( i3.ge.1 .and. i3+31.le.NP2 ) &
|
|
term3=abs(sum(cd0(i3:i3+31)*conjg(ctwk*csync(i,1:32))))
|
|
sync=sync+term1+term2+term3
|
|
enddo
|
|
if( sync .gt. smax ) then
|
|
smax=sync
|
|
delfbest=delf
|
|
endif
|
|
enddo
|
|
a=0.0
|
|
a(1)=-delfbest
|
|
call twkfreq1(cd0,NP2,fs2,a,cd0)
|
|
xdt=xdt2
|
|
f1=f1+delfbest
|
|
|
|
j=0
|
|
do k=1,NN
|
|
i1=ibest+(k-1)*32
|
|
csymb=cmplx(0.0,0.0)
|
|
if( i1.ge.1 .and. i1+31 .le. NP2 ) csymb=cd0(i1:i1+31)
|
|
call four2a(csymb,32,1,-1,1)
|
|
s2(0:7,k)=abs(csymb(1:8))
|
|
enddo
|
|
j=0
|
|
do k=1,NN
|
|
if(k.le.7) cycle
|
|
if(k.ge.37 .and. k.le.43) cycle
|
|
if(k.gt.72) cycle
|
|
j=j+1
|
|
s1(0:7,j)=s2(0:7,k)
|
|
enddo
|
|
|
|
do j=1,ND
|
|
ps=s1(0:7,j)
|
|
where (ps.gt.0.0) ps=log(ps)
|
|
r1=max(ps(1),ps(3),ps(5),ps(7))-max(ps(0),ps(2),ps(4),ps(6))
|
|
r2=max(ps(2),ps(3),ps(6),ps(7))-max(ps(0),ps(1),ps(4),ps(5))
|
|
r4=max(ps(4),ps(5),ps(6),ps(7))-max(ps(0),ps(1),ps(2),ps(3))
|
|
rxdata(3*j-2)=r4
|
|
rxdata(3*j-1)=r2
|
|
rxdata(3*j)=r1
|
|
enddo
|
|
|
|
rxav=sum(rxdata)/(3.0*ND)
|
|
rx2av=sum(rxdata*rxdata)/(3.0*ND)
|
|
var=rx2av-rxav*rxav
|
|
if( var .gt. 0.0 ) then
|
|
rxsig=sqrt(var)
|
|
else
|
|
rxsig=sqrt(rx2av)
|
|
endif
|
|
rxdata=rxdata/rxsig
|
|
ss=0.84
|
|
llr=2.0*rxdata/(ss*ss)
|
|
apmask=0
|
|
cw=0
|
|
call timer('bpd174 ',0)
|
|
call bpdecode174(llr,apmask,max_iterations,decoded,cw,nharderrors)
|
|
call timer('bpd174 ',1)
|
|
dmin=0.0
|
|
if(nharderrors.lt.0) then
|
|
call timer('osd174 ',0)
|
|
call osd174(llr,norder,decoded,cw,nharderrors,dmin)
|
|
call timer('osd174 ',1)
|
|
endif
|
|
nbadcrc=1
|
|
message=' '
|
|
xsnr=-99.0
|
|
if(count(cw.eq.0).eq.174) go to 900 !Reject the all-zero codeword
|
|
if( nharderrors.ge.0 .and. dmin.le.30.0 .and. nharderrors .lt. 30) then
|
|
call chkcrc12a(decoded,nbadcrc)
|
|
else
|
|
nharderrors=-1
|
|
go to 900
|
|
endif
|
|
if(nbadcrc.eq.0) then
|
|
call extractmessage174(decoded,message,ncrcflag,recent_calls,nrecent)
|
|
call genft8(message,msgsent,itone)
|
|
xsig=0.0
|
|
xnoi=0.0
|
|
do i=1,79
|
|
xsig=xsig+s2(itone(i),i)**2
|
|
ios=mod(itone(i)+4,7)
|
|
xnoi=xnoi+s2(ios,i)**2
|
|
enddo
|
|
xsnr=0.001
|
|
if( xnoi.gt.0 .and. xnoi.lt.xsig ) xsnr=xsig/xnoi-1.0
|
|
xsnr=10.0*log10(xsnr)-27.0
|
|
if( xsnr .lt. -24.0 ) xsnr=-24.0
|
|
endif
|
|
900 continue
|
|
return
|
|
end subroutine ft8b
|
|
|
|
subroutine ft8_downsample(dd,newdat,f0,c1)
|
|
|
|
! Downconvert to complex data sampled at 187.5 Hz, 32 samples/symbol
|
|
|
|
parameter (NMAX=15*12000)
|
|
parameter (NFFT1=200000,NFFT2=3125) !200000/64 = 3125
|
|
logical newdat
|
|
complex c1(0:NFFT2-1)
|
|
complex cx(0:NFFT1/2)
|
|
real dd(NMAX),x(NFFT1)
|
|
equivalence (x,cx)
|
|
save cx
|
|
|
|
if(newdat) then
|
|
! Data in dd have changed, recompute the long FFT
|
|
x(1:NMAX)=dd
|
|
x(NMAX+1:NFFT1)=0. !Zero-pad the x array
|
|
call four2a(cx,NFFT1,1,-1,0) !r2c FFT to freq domain
|
|
newdat=.false.
|
|
endif
|
|
|
|
df=12000.0/NFFT1
|
|
baud=12000.0/2048.0
|
|
i0=nint(f0/df)
|
|
ft=f0+8.0*baud
|
|
it=min(nint(ft/df),NFFT1/2)
|
|
fb=f0-1.0*baud
|
|
ib=max(1,nint(fb/df))
|
|
k=0
|
|
c1=0.
|
|
do i=ib,it
|
|
c1(k)=cx(i)
|
|
k=k+1
|
|
enddo
|
|
c1=cshift(c1,i0-ib)
|
|
call four2a(c1,NFFT2,1,1,1) !c2c FFT back to time domain
|
|
fac=1.0/sqrt(float(NFFT1)*NFFT2)
|
|
c1=fac*c1
|
|
|
|
return
|
|
end subroutine ft8_downsample
|