mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2025-10-30 20:40:28 -04:00
31 lines
666 B
Fortran
31 lines
666 B
Fortran
subroutine twkfreq(c3,c4,npts,fsample,a)
|
|
|
|
! Adjust frequency of complex data
|
|
! a(1) Hz
|
|
! a(2) Hz/(0.5*TxT), where TxT = npts/fsample = file duration
|
|
|
|
complex c3(npts)
|
|
complex c4(npts)
|
|
complex w,wstep
|
|
real a(3)
|
|
data twopi/6.283185307/
|
|
|
|
! Mix the complex signal
|
|
w=1.0
|
|
wstep=1.0
|
|
x0=0.5*(npts+1)
|
|
s=2.0/npts
|
|
do i=1,npts
|
|
x=s*(i-x0)
|
|
p2=1.5*x*x - 0.5
|
|
! p3=2.5*(x**3) - 1.5*x
|
|
! p4=4.375*(x**4) - 3.75*(x**2) + 0.375
|
|
dphi=(a(1) + x*a(2) + p2*a(3)) * (twopi/fsample)
|
|
wstep=cmplx(cos(dphi),sin(dphi))
|
|
w=w*wstep
|
|
c4(i)=w*c3(i)
|
|
enddo
|
|
|
|
return
|
|
end subroutine twkfreq
|