Phase Shift

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

  1. mau80

    Thread Starter New Member

    Oct 24, 2010
    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°.

    I’d like to ask some help about this problem and why I get a result different from exercise.

    Thank you very much!

  2. guitarguy12387

    Active Member

    Apr 10, 2008
    It's the same angle... matlab probably just converts to positive angle by default
  3. mau80

    Thread Starter New Member

    Oct 24, 2010
    Thank you very much for your reply.

    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
  4. jegues

    Well-Known Member

    Sep 13, 2010
    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.