mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2024-11-17 17:42:02 -05:00
8a8bb89e44
git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@7197 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
90 lines
2.1 KiB
Fortran
90 lines
2.1 KiB
Fortran
subroutine sh65(cx,n5,mode65,ntol,xdf,nspecial,snrdb)
|
|
parameter(NFFT=2048,NH=NFFT/2,MAXSTEPS=150)
|
|
complex cx(90000)
|
|
complex c(0:NFFT-1)
|
|
real s(-NH+1:NH)
|
|
real s2(-NH+1:NH,MAXSTEPS)
|
|
real ss(-NH+1:NH,8)
|
|
real sigmax(8)
|
|
integer ipk(8)
|
|
|
|
s=0.
|
|
ss=0.
|
|
|
|
jstep=NFFT/4
|
|
nblks=n5/jstep - 3
|
|
ia=-jstep+1
|
|
do iblk=1,nblks
|
|
ia=ia+jstep
|
|
ib=ia+NFFT-1
|
|
c=cx(ia:ib)
|
|
call four2a(c,nfft,1,1,1) !c2c FFT
|
|
do i=0,NFFT-1
|
|
j=i
|
|
if(j.gt.NH) j=j-NFFT
|
|
p=real(c(i))**2 + aimag(c(i))**2
|
|
s(j)=s(j) + p
|
|
s2(j,iblk)=p
|
|
enddo
|
|
n=mod(iblk-1,8) +1
|
|
ss(-NH+1:NH,n)=ss(-NH+1:NH,n) + s2(-NH+1:NH,iblk)
|
|
enddo
|
|
|
|
s=1.e-6*s
|
|
ss=1.e-6*ss
|
|
df=1378.1285/NFFT
|
|
nfac=40*mode65
|
|
dtstep=0.25/df
|
|
|
|
! Define range of frequencies to be searched
|
|
fa=-ntol
|
|
fb=ntol
|
|
ia2=max(-NH+1,nint(fa/df))
|
|
! Upper tone is above sync tone by 4*nfac*df Hz
|
|
ib2=min(NH,nint(fb/df + 4.1*nfac))
|
|
|
|
! Find strongest line in each of the 4 phases, repeating for each drift rate.
|
|
sbest=0.
|
|
snrbest=0.
|
|
nbest=1
|
|
ipk=0
|
|
|
|
do n=1,8
|
|
sigmax(n)=0.
|
|
do i=ia2,ib2
|
|
sig=ss(i,n)
|
|
if(sig.ge.sigmax(n)) then
|
|
ipk(n)=i
|
|
sigmax(n)=sig
|
|
if(sig.ge.sbest) then
|
|
sbest=sig
|
|
nbest=n
|
|
endif
|
|
endif
|
|
enddo
|
|
enddo
|
|
n2best=nbest+4
|
|
if(n2best.gt.8) n2best=nbest-4
|
|
xdf=min(ipk(nbest),ipk(n2best))*df
|
|
nspecial=0
|
|
if(abs(xdf).le.ntol) then
|
|
idiff=abs(ipk(nbest)-ipk(n2best))
|
|
xk=float(idiff)/nfac
|
|
k=nint(xk)
|
|
iderr=nint((xk-k)*nfac)
|
|
! maxerr=nint(0.008*abs(idiff) + 0.51)
|
|
maxerr=nint(0.02*abs(idiff) + 0.51) !### Better test ??? ###
|
|
if(abs(iderr).le.maxerr .and. k.ge.2 .and. k.le.4) nspecial=k
|
|
snrdb=-30.0
|
|
if(nspecial.gt.0) then
|
|
call sh65snr(ss(ia2,nbest),ib2-ia2+1,snr1)
|
|
call sh65snr(ss(ia2,n2best),ib2-ia2+1,snr2)
|
|
snr=0.5*(snr1+snr2)
|
|
snrdb=db(snr) - db(2500.0/df) - db(sqrt(nblks/4.0)) + 8.0
|
|
endif
|
|
if(snr1.lt.4.0 .or. snr2.lt.4.0 .or. snr.lt.5.0) nspecial=0
|
|
endif
|
|
|
|
return
|
|
end subroutine sh65
|