mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2024-11-16 09:01:59 -05:00
44 lines
837 B
Fortran
44 lines
837 B
Fortran
subroutine lorentzian_fading(c,npts,fs,fspread)
|
|
!
|
|
! npts is the total length of the simulated data vector
|
|
!
|
|
complex c(0:npts-1)
|
|
complex cspread(0:npts-1)
|
|
complex z
|
|
|
|
twopi=8.0*atan(1.0)
|
|
df=fs/npts
|
|
nh=npts/2
|
|
cspread(0)=1.0
|
|
cspread(nh)=0.
|
|
b=6.0
|
|
do i=1,nh
|
|
f=i*df
|
|
x=b*f/fspread
|
|
z=0.
|
|
a=0.
|
|
if(x.lt.3.0) then
|
|
a=sqrt(1.111/(1.0+x*x)-0.1)
|
|
phi1=twopi*rran()
|
|
z=a*cmplx(cos(phi1),sin(phi1))
|
|
endif
|
|
cspread(i)=z
|
|
z=0.
|
|
if(x.lt.3.0) then
|
|
phi2=twopi*rran()
|
|
z=a*cmplx(cos(phi2),sin(phi2))
|
|
endif
|
|
cspread(npts-i)=z
|
|
enddo
|
|
|
|
call four2a(cspread,npts,1,1,1)
|
|
|
|
s=sum(abs(cspread)**2)
|
|
avep=s/npts
|
|
fac=sqrt(1.0/avep)
|
|
cspread=fac*cspread
|
|
c=cspread*c
|
|
|
|
return
|
|
end subroutine lorentzian_fading
|