WSJT-X/map65/libm65/wideband2_sync.f90
2021-05-11 14:53:49 -04:00

116 lines
2.8 KiB
Fortran

module wideband2_sync
parameter (NFFT=32768)
integer isync(22)
integer nkhz_center
real sync_dat(NFFT,6) !fkhz, ccfmax, xdt, ipol, flip
real savg_med(4)
contains
subroutine wb2_sync(ss,savg,nfa,nfb)
! Compute "orange sync curve" using the Q65 sync pattern
parameter (LAGMAX=30)
real ss(4,322,NFFT)
real savg(4,NFFT)
logical first
integer isync0(22)
integer jsync0(63)
! Q65 sync symbols
data isync0/1,9,12,13,15,22,23,26,27,33,35,38,46,50,55,60,62,66,69,74,76,85/
data jsync0/ &
1, 4, 5, 9, 10, 11, 12, 13, 14, 16, 18, 22, 24, 25, 28, 32, &
33, 34, 37, 38, 39, 40, 42, 43, 45, 46, 47, 48, 52, 53, 55, 57, &
59, 60, 63, 64, 66, 68, 70, 73, 80, 81, 89, 90, 92, 95, 97, 98, &
100,102,104,107,108,111,114,119,120,121,122,123,124,125,126/
data first/.true./
save first
do j=322,1,-1
if(sum(ss(1,j,1:NFFT)).gt.0.0) exit
enddo
jz=j
tstep=2048.0/11025.0 !0.185760 s: 0.5*tsym_jt65, 0.3096*tsym_q65
if(first) then
fac=0.6/tstep
do i=1,22 !Expand the Q65 sync stride
isync(i)=nint((isync0(i)-1)*fac) + 1
enddo
do i=1,63
jsync0(i)=2*(jsync0(i)-1) + 1
enddo
first=.false.
endif
df3=96000.0/NFFT
ia=nint(1000*nfa/df3) !Flat frequency range for WSE converters
ib=nint(1000*nfb/df3)
do i=1,4
call pctile(savg(i,ia:ib),ib-ia+1,50,savg_med(i))
enddo
do i=ia,ib
write(14,3014) 0.001*i*df3,savg(1:4,i)
3014 format(5f10.3)
enddo
lagbest=0
ipolbest=1
flip=0.
do i=ia,ib
ccfmax=0.
do ipol=1,4
do lag=0,LAGMAX
ccf=0.
do j=1,22
k=isync(j) + lag
ccf=ccf + ss(ipol,k,i+1) + ss(ipol,k+1,i+1) + ss(ipol,k+2,i+1)
enddo
ccf=ccf - savg(ipol,i+1)*3*22/float(jz)
if(ccf.gt.ccfmax) then
ipolbest=ipol
lagbest=lag
ccfmax=ccf
flip=0.
endif
ccf=0.
do j=1,63
k=jsync0(j) + lag
ccf=ccf + ss(ipol,k,i+1) + ss(ipol,k+1,i+1)
enddo
ccf=ccf - savg(ipol,i+1)*2*63/float(jz)
if(ccf.gt.ccfmax) then
ipolbest=ipol
lagbest=lag
ccfmax=ccf
flip=1.0
endif
enddo ! lag
enddo !ipol
fkhz=0.001*i*df3 + nkhz_center - 48.0
xdt=lagbest*tstep-1.0
sync_dat(i,1)=fkhz
sync_dat(i,2)=ccfmax
sync_dat(i,3)=xdt
sync_dat(i,4)=ipolbest
sync_dat(i,5)=flip
sync_dat(i,6)=ccfmax/(savg(ipolbest,i)/savg_med(ipolbest))
enddo
call pctile(sync_dat(ia:ib,2),ib-ia+1,50,base)
sync_dat(ia:ib,2)=sync_dat(ia:ib,2)/base
return
end subroutine wb2_sync
end module wideband2_sync