Phase is affected by windowing?

Hello for everybody!!!!!!!!!!!!!

I write a program for FHT(Hartley) and i wtite a flat top, hanning and
hamming window function everything is ok here. Im analysing 2 signal of 60
Hz both.

v=sin(2pif)
i=sin(2pif-theta_i)
theta=theta_v-theta_i

if theta_i is between 0-27 degrees and theta_v=0 there�s no problem theta=
angle between 0-27 but if theta_i is for example 28 or more  (theta_v = 0)
theta=-152, i dont know what happend, Can anyone help me?
Im gonna appreciate. Tahnks!!!!!!!!! 

On Oct 5, 5:50 pm, "Salvadorr" <salpi...@hotmail.com> wrote:
> Hello for everybody!!!!!!!!!!!!!
>
> I write a program for FHT(Hartley) and i wtite a flat top, hanning and
> hamming window function everything is ok here. Im analysing 2 signal of 60
> Hz both.
>
> v=3Dsin(2pif)
> i=3Dsin(2pif-theta_i)
> theta=3Dtheta_v-theta_i
>
> if theta_i is between 0-27 degrees and theta_v=3D0 there=B4s no problem t=
heta=3D
> angle between 0-27 but if theta_i is for example 28 or more  (theta_v =3D=
 0)
> theta=3D-152, i dont know what happend, Can anyone help me?

Note that 28 + 152 =3D 180 degrees of phase.
This is the type of difference that using an atan() instead of an
atan2() function can produce.

Salvadorr skrev:

> I write a program for FHT(Hartley) and i wtite a flat top, hanning and
> hamming window function everything is ok here. Im analysing 2 signal of 60
> Hz both.
>
> v=3Dsin(2pif)
> i=3Dsin(2pif-theta_i)
> theta=3Dtheta_v-theta_i
>
> if theta_i is between 0-27 degrees and theta_v=3D0 there=B4s no problem t=
heta=3D
> angle between 0-27 but if theta_i is for example 28 or more  (theta_v =3D=
 0)
> theta=3D-152, i dont know what happend, Can anyone help me?

What you write here mixes radians and degrees. You do, of course,
convert from degrees to radians in you computations?

Rune

I use atan2, it was OK, Thanks for your time. Really thanks!!!!!!!!!!!!!