1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
|
subroutine ccf2(ss,nz,nflip,ccfbest,xlagpk)
! parameter (LAGMIN=-86,LAGMAX=258)
parameter (LAGMIN=-112,LAGMAX=258) ! Look for DT from -3.6s to +5.0s
real ss(nz)
real ccf(-LAGMAX:LAGMAX)
integer npr(126)
! The JT65 pseudo-random sync pattern:
data npr/ &
1,0,0,1,1,0,0,0,1,1,1,1,1,1,0,1,0,1,0,0, &
0,1,0,1,1,0,0,1,0,0,0,1,1,1,0,0,1,1,1,1, &
0,1,1,0,1,1,1,1,0,0,0,1,1,0,1,0,1,0,1,1, &
0,0,1,1,0,1,0,1,0,1,0,0,1,0,0,0,0,0,0,1, &
1,0,0,0,0,0,0,0,1,1,0,1,0,0,1,0,1,1,0,1, &
0,1,0,1,0,0,1,1,0,0,1,0,0,1,0,0,0,0,1,1, &
1,1,1,1,1,1/
save
ccfbest=0.
lag1=LAGMIN
lag2=LAGMAX
do lag=lag1,lag2
s0=0.
s1=0.
do i=1,126
j=16*(i-1)+1 + lag
if(j.ge.1 .and. j.le.nz-8) then
x=ss(j)
if(npr(i).eq.0) then
s0=s0 + x
else
s1=s1 + x
endif
endif
enddo
ccf(lag)=nflip*(s1-s0)
if(ccf(lag).gt.ccfbest) then
ccfbest=ccf(lag)
lagpk=lag
xlagpk=lagpk
endif
enddo
if( lagpk.gt.-LAGMAX .and. lagpk.lt.LAGMAX) then
call peakup(ccf(lagpk-1),ccf(lagpk),ccf(lagpk+1),dx)
xlagpk=lagpk+dx
endif
return
end subroutine ccf2
|
