WSJT-X/lib/sync9.f90

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Fortran
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subroutine sync9(ss,nzhsym,lag1,lag2,ia,ib,ccfred,red2,ipkbest)
include 'constants.f90'
real ss(184,NSMAX)
real ss1(184)
real ccfred(NSMAX)
real savg(NSMAX)
real savg2(NSMAX)
real smo(-5:25)
real sq(NSMAX)
real red2(NSMAX)
character*27 cr
data cr/'(C) 2016, Joe Taylor - K1JT'/
include 'jt9sync.f90'
ipk=0
ipkbest=0
sbest=0.
ccfred=0.
do i=ia,ib !Loop over freq range
ss1=ss(1:184,i)
call pctile(ss1,nzhsym,40,xmed)
ss1=ss1/xmed - 1.0
do j=1,nzhsym
if(ss1(j).gt.3.0) ss1(j)=3.0
enddo
call pctile(ss1,nzhsym,45,sbase)
ss1=ss1-sbase
sq0=dot_product(ss1(1:nzhsym),ss1(1:nzhsym))
rms=sqrt(sq0/(nzhsym-1))
smax=0.
do lag=lag1,lag2 !DT = 2.5 to 5.0 s
sum1=0.
sq2=sq0
nsum=nzhsym
do j=1,16 !Sum over 16 sync symbols
k=ii2(j) + lag
if(k.ge.1 .and. k.le.nzhsym) then
sum1=sum1 + ss1(k)
sq2=sq2 - ss1(k)*ss1(k)
nsum=nsum-1
endif
enddo
if(sum1.gt.smax) then
smax=sum1
ipk=i
endif
rms=sqrt(sq2/(nsum-1))
enddo
ccfred(i)=smax !Best at this freq, over all lags
if(smax.gt.sbest) then
sbest=smax
ipkbest=ipk
endif
enddo
call pctile(ccfred(ia),ib-ia+1,50,xmed)
if(xmed.le.0.0) xmed=1.0
ccfred=2.0*ccfred/xmed
savg=0.
do j=1,nzhsym
savg(ia:ib)=savg(ia:ib) + ss(j,ia:ib)
enddo
savg(ia:ib)=savg(ia:ib)/nzhsym
smo(0:20)=1.0/21.0
smo(-5:-1)=-(1.0/21.0)*(21.0/10.0)
smo(21:25)=smo(-5)
do i=ia,ib
sm=0.
do j=-5,25
if(i+j.ge.1 .and. i+j.lt.NSMAX) sm=sm + smo(j)*savg(i+j)
enddo
savg2(i)=sm
sq(i)=sm*sm
enddo
call pctile(sq(ia:ib),ib-ia+1,20,sq0)
rms=sqrt(sq0)
savg2(ia:ib)=savg2(ia:ib)/(5.0*rms)
red2=0.
do i=ia+11,ib-10
ref=max(savg2(i-10),savg2(i+10))
red2(i)=savg2(i)-ref
if(red2(i).lt.-99.0) red2(i)=-99.0
if(red2(i).gt.99.0) red2(i)=99.0
enddo
return
end subroutine sync9