2012-05-22 13:09:48 -04:00
|
|
|
subroutine ccf2(ss,nz,nflip,ccfbest,lagpk)
|
|
|
|
|
|
|
|
|
|
parameter (LAGMAX=60)
|
|
|
|
|
! parameter (LAGMAX=200)
|
|
|
|
|
real ss(nz)
|
|
|
|
|
real ccf(-LAGMAX:LAGMAX)
|
|
|
|
|
integer npr(126)
|
|
|
|
|
|
|
|
|
|
C 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=-LAGMAX
|
|
|
|
|
lag2=LAGMAX
|
|
|
|
|
do lag=lag1,lag2
|
|
|
|
|
s0=0.
|
|
|
|
|
s1=0.
|
|
|
|
|
do i=1,126
|
|
|
|
|
j=2*(8*i + 43) + lag
|
|
|
|
|
if(j.ge.1 .and. j.le.nz-8) then
|
|
|
|
|
x=ss(j)+ss(j+8) !Add two half-symbol contributions
|
|
|
|
|
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
|
|
|
|
|
endif
|
|
|
|
|
enddo
|
|
|
|
|
|
|
|
|
|
return
|
|
|
|
|
end
|
