mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2024-11-04 16:31:17 -05:00
38 lines
874 B
Fortran
38 lines
874 B
Fortran
|
subroutine peakdf9(c0,npts8,nsps8,istart,foffset,xdf)
|
||
|
|
|
||
|
|
complex c0(0:npts8-1)
|
||
|
|
complex zsum
|
||
|
|
integer ii(16) !Locations of sync symbols
|
||
|
|
data ii/1,6,11,16,21,26,31,39,45,51,57,63,69,75,81,85/
|
||
|
|
|
||
|
|
twopi=8.0*atan(1.0)
|
||
|
|
df=1500.0/nsps8
|
||
|
|
smax=0.
|
||
|
|
do idf=-10,10
|
||
|
|
f0=foffset + 0.1*df*idf
|
||
|
|
dphi=twopi*f0/1500.0
|
||
|
|
sum=0.
|
||
|
|
do j=1,16
|
||
|
|
i1=(ii(j)-1)*nsps8 + istart
|
||
|
|
phi=0.
|
||
|
|
zsum=0.
|
||
|
|
do i=i1,i1+nsps8-1
|
||
|
|
if(i.lt.0) cycle
|
||
|
|
phi=phi + dphi
|
||
|
|
zsum=zsum + c0(i) * cmplx(cos(phi),-sin(phi))
|
||
|
|
enddo
|
||
|
|
sum=sum + real(zsum)**2 + aimag(zsum)**2
|
||
|
|
enddo
|
||
|
|
if(sum.gt.smax) then
|
||
|
|
idfpk=idf
|
||
|
|
fpk=f0
|
||
|
|
smax=sum
|
||
|
|
endif
|
||
|
|
enddo
|
||
|
|
|
||
|
|
write(*,3001) idfpk,fpk,smax
|
||
|
|
3001 format('DF:'i5,f8.2,f12.3)
|
||
|
|
|
||
|
|
return
|
||
|
|
end subroutine peakdf9
|