WSJT-X/lib/sync_qra65.f90

111 lines
2.8 KiB
Fortran

subroutine sync_qra65(iwave,nmax,mode65,nsps,nfqso,ntol,xdt,f0,snr1)
parameter (NSTEP=4) !Quarter-symbol steps
integer*2 iwave(0:nmax-1) !Raw data
integer isync(22) !Indices of sync symbols
integer ijpk(2) !Indices i and j at peak of ccf
real, allocatable :: s1(:,:) !Symbol spectra, quarter-symbol steps
real sync(85) !sync vector
real ccf(-64:64,-15:15)
complex, allocatable :: c0(:) !Complex spectrum of symbol
data isync/1,9,12,13,15,22,23,26,27,33,35,38,46,50,55,60,62,66,69,74,76,85/
data sync(1)/99.0/
save sync
nfft=2*nsps
df=12000.0/nfft
istep=nsps/NSTEP
iz=5000.0/df !Uppermost frequency bin, at 5000 Hz
txt=85.0*nsps/12000.0
jz=(txt+1.0)*12000.0/istep !Number of quarter-symbol steps
if(nsps.ge.7680) jz=(txt+2.0)*12000.0/istep !For TR 60 s and higher
allocate(s1(iz,jz))
allocate(c0(0:nfft-1))
if(sync(1).eq.99.0) then
sync=-22.0/63.0 !Sync OFF
do k=1,22
sync(isync(k))=1.0 !Sync ON
enddo
endif
fac=1/32767.0
do j=1,jz !Compute symbol spectra at quarter-symbol steps
ia=(j-1)*istep
ib=ia+nsps-1
k=-1
do i=ia,ib,2
xx=iwave(i)
yy=iwave(i+1)
k=k+1
c0(k)=fac*cmplx(xx,yy)
enddo
c0(k+1:)=0.
call four2a(c0,nfft,1,-1,0) !r2c FFT
do i=1,iz
s1(i,j)=real(c0(i))**2 + aimag(c0(i))**2
enddo
enddo
i0=nint(nfqso/df)
call pctile(s1(i0-64:i0+192,1:jz),129*jz,40,base)
s1=s1/base
s1max=20.0
! Apply AGC
do j=1,jz
smax=maxval(s1(i0-64:i0+192,j))
if(smax.gt.s1max) s1(i0-64:i0+192,j)=s1(i0-64:i0+192,j)*s1max/smax
enddo
! do i=1,iz
! write(60,3060) i,i*df,sum(s1(i,1:jz))
!3060 format(i6,f10.3,e12.3)
! enddo
ccf=0.
ia=min(64,nint(ntol/df))
jadd=11
if(nsps.ge.3600) jadd=7
if(nsps.ge.7680) jadd=6
if(nsps.ge.16000) jadd=3
if(nsps.ge.41472) jadd=1
dt4=nsps/(NSTEP*12000.0) !1/4 of symbol duration
! print*,'DT range +/-',15*dt4
! j0=0.5/dt4
! if(nsps.ge.7680) j0=1.0/dt4
do i=-ia,ia
do lag=-15,15
do k=1,85
n=NSTEP*(k-1) + 1
j=n+lag+jadd
if(j.ge.1 .and. j.le.jz) then
ccf(i,lag)=ccf(i,lag) + sync(k)*s1(i0+i,j)
endif
enddo
enddo
enddo
! do i=-64,64
! write(61,3061) i,ccf(i,jpk)
!3061 format(i5,e12.3)
! enddo
! do j=-15,15
! write(62,3061) j,ccf(ipk,j)
! enddo
ijpk=maxloc(ccf)
ipk=ijpk(1)-65
jpk=ijpk(2)-16
f0=nfqso + ipk*df
xdt=jpk*dt4
snr1=maxval(ccf)/22.0
! write(*,3100) ipk,jpk,xdt,f0,snr1
!3100 format(2i5,f7.2,2f10.2)
return
end subroutine sync_qra65