mirror of https://github.com/saitohirga/WSJT-X.git
123 lines
3.9 KiB
Fortran
123 lines
3.9 KiB
Fortran
subroutine sync64(dd,nf1,nf2,nfqso,ntol,mode64,maxf1,dtx,f0,jpk,kpk,snrdb,c0)
|
|
|
|
parameter (NMAX=60*12000) !Max size of raw data at 12000 Hz
|
|
parameter (NSPS=2304) !Samples per symbol at 4000 Hz
|
|
parameter (NSPC=7*NSPS) !Samples per Costas array
|
|
real dd(NMAX) !Raw data
|
|
real s1(0:NSPC-1) !Power spectrum of Costas 1
|
|
real s2(0:NSPC-1) !Power spectrum of Costas 2
|
|
real s3(0:NSPC-1) !Power spectrum of Costas 3
|
|
real s0(0:NSPC-1) !Sum of s1+s2+s3
|
|
real s0a(0:NSPC-1) !Best synchromized spectrum (saved)
|
|
real s0b(0:NSPC-1) !tmp
|
|
integer icos7(0:6) !Costas 7x7 tones
|
|
integer ipk0(1)
|
|
complex cc(0:NSPC-1) !Costas waveform
|
|
complex c0(0:360000) !Complex spectrum of dd()
|
|
complex c1(0:NSPC-1) !Complex spectrum of Costas 1
|
|
complex c2(0:NSPC-1) !Complex spectrum of Costas 2
|
|
complex c3(0:NSPC-1) !Complex spectrum of Costas 3
|
|
data icos7/2,5,6,0,4,1,3/ !Costas 7x7 tone pattern
|
|
data mode64z/-1/
|
|
save
|
|
|
|
if(mode64.ne.mode64z) then
|
|
twopi=8.0*atan(1.0)
|
|
dfgen=mode64*12000.0/6912.0
|
|
k=-1
|
|
phi=0.
|
|
do j=0,6 !Compute complex Costas waveform
|
|
dphi=twopi*icos7(j)*dfgen/4000.0
|
|
do i=1,2304
|
|
phi=phi + dphi
|
|
if(phi.gt.twopi) phi=phi-twopi
|
|
k=k+1
|
|
cc(k)=cmplx(cos(phi),sin(phi))
|
|
enddo
|
|
enddo
|
|
mode64z=mode64
|
|
endif
|
|
|
|
npts0=54*12000
|
|
nfft1=672000
|
|
nfft2=nfft1/3
|
|
df1=12000.0/nfft1
|
|
fac=2.0/nfft1
|
|
do i=0,nfft1/2 !Load real data into c0
|
|
c0(i)=fac*cmplx(dd(1+2*i),dd(2+2*i))
|
|
enddo
|
|
call four2a(c0,nfft1,1,-1,0) !Forward r2c FFT
|
|
call four2a(c0,nfft2,1,1,1) !Inverse c2c FFT; c0 is analytic sig
|
|
npts2=npts0/3 !Downsampled complex data length
|
|
nfft3=NSPC
|
|
nh3=nfft3/2
|
|
df3=4000.0/nfft3
|
|
fa=max(nf1,nfqso-ntol)
|
|
fb=min(nf2,nfqso+ntol)
|
|
ia=max(maxf1,nint(fa/df3))
|
|
ib=min(NSPC-1-maxf1,nint(fb/df3))
|
|
iz=ib-ia+1
|
|
snr=0.
|
|
jpk=0
|
|
ja=0
|
|
jb=6*4000
|
|
jstep=200
|
|
ka=-maxf1
|
|
kb=maxf1
|
|
ipk=0
|
|
kpk=0
|
|
do iter=1,2
|
|
do j1=ja,jb,jstep
|
|
j2=j1 + 39*2304
|
|
j3=j1 + 77*2304
|
|
c1=1.e-4*c0(j1:j1+NSPC-1) * conjg(cc)
|
|
call four2a(c1,nfft3,1,-1,1)
|
|
c2=1.e-4*c0(j2:j2+NSPC-1) * conjg(cc)
|
|
call four2a(c2,nfft3,1,-1,1)
|
|
c3=1.e-4*c0(j3:j3+NSPC-1) * conjg(cc)
|
|
call four2a(c3,nfft3,1,-1,1)
|
|
s0=0.
|
|
s1=0.
|
|
s2=0.
|
|
s3=0.
|
|
do i=ia,ib
|
|
freq=i*df3
|
|
s1(i)=real(c1(i))**2 + aimag(c1(i))**2
|
|
s2(i)=real(c2(i))**2 + aimag(c2(i))**2
|
|
s3(i)=real(c3(i))**2 + aimag(c3(i))**2
|
|
enddo
|
|
do k=ka,kb
|
|
s0b(ia:ib)=s1(ia-k:ib-k) + s2(ia:ib) + s3(ia+k:ib+k)
|
|
s0b(:ia-1)=0.
|
|
s0b(ib+1:)=0.
|
|
nadd=(7*mode64)/2
|
|
if(mod(nadd,2).eq.1) nadd=nadd+1 !Make nadd odd
|
|
if(nadd.ge.3) call smo(s0b(ia:ib),iz,s0(ia:ib),nadd)
|
|
call smo121(s0(ia:ib),iz)
|
|
nskip=max(14,2*mode64)
|
|
call averms(s0(ia:ib),iz,nskip,ave,rms)
|
|
s=(maxval(s0(ia:ib))-ave)/rms
|
|
if(s.gt.snr) then
|
|
jpk=j1
|
|
s0a=s0/rms
|
|
snr=s
|
|
dtx=jpk/4000.0 - 1.0
|
|
ipk0=maxloc(s0(ia:ib))
|
|
ipk=ipk0(1)
|
|
f0=(ipk+ia-1)*df3
|
|
kpk=k
|
|
endif
|
|
enddo
|
|
enddo
|
|
ja=max(0,jpk-2*jstep)
|
|
jb=min(336000-NSPC,jpk+2*jstep)
|
|
jstep=10
|
|
enddo
|
|
|
|
write(17) ia,ib,s0a(ia:ib) !Save data for red curve
|
|
close(17)
|
|
snrdb=10.0*log10(snr)-39.0
|
|
|
|
return
|
|
end subroutine sync64
|