# Phase Shift

Discussion in 'Homework Help' started by mau80, May 30, 2011.

1. ### mau80 Thread Starter New Member

Oct 24, 2010
21
0
Hi to all,

I'd like to ask a question related to phase shift.

In attachment there is a complete description of text and solution and my Matlab simulation.

I've to computate a phase shift of a circuit with an AMP.OP, when I give in input a sinusoidal signal.

After retrive transfer function is s domain:

Av(s) => s=jw >= Av(jw)

After I compute:

angle(jw) = 1.7904
1.709 correspond to 102.583°

The solution proposed is -257°.

Thank you very much!

Regards
Maurizio

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2. ### guitarguy12387 Active Member

Apr 10, 2008
359
12
It's the same angle... matlab probably just converts to positive angle by default

3. ### mau80 Thread Starter New Member

Oct 24, 2010
21
0

Ok the angle is the same:

0° - 102.583° = - 257.417°

My doubt is related to sign of angle that is negative instead of positive.

Says that the system introduce a phase shift of 102° or phase shift of -257° is the same thing?

Thank you very much for your great help!

Best Regards
Maurizio

4. ### jegues Well-Known Member

Sep 13, 2010
732
45
Yes, draw a unit circle.

You can either travel 102° in the positive direction or -257° in the negative direction.

Regardless which one you choose you will end up on the same spot in the unit circle.