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Homework Help: Can't see the error in the transfer function

  1. Jan 18, 2015 #1


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    Homework Helper

    1. The problem statement, all variables and given/known data

    Here is the problem:

    Screen Shot 2015-01-18 at 2.24.54 PM.png
    Screen Shot 2015-01-18 at 2.25.07 PM.png

    2. Relevant equations

    3. The attempt at a solution

    Okay so I was REALLY confused as to why something wrong happened. Here is my work for the whole question:


    Sorry for the terrible writing.

    Okay so for part a), I derived the transfer function as required. I had to be careful about the impedance of the capacitor though. Then I went to fill in the table and I got the results displayed above.

    It appears the bode plot information in part a) is correct by looking at part b), which indicates a high-pass.

    What doesn't make any sense though is the phase plot. The phase characteristics I found in part b) are clearly correct, but do not match up to part a) at all.

    I have been staring at this for an hour now and I can't see what's going wrong. Could someone shed some light on this?

    Thank you.

    EDIT: Please note for part a), I computed the phase ##\Delta \phi## by using:

    ##\Delta \phi = - \text{arctan}(\frac{\omega}{\frac{10^6}{1.2}})##

    EDIT2: Wait wait I think I figured it out, I forgot about the ##90^o## angle for part a), so that would mean:

    ##\Delta \phi = 90^o - \text{arctan}(\frac{\omega}{\frac{10^6}{1.2}})##


    Never mind guys, everything appears to make sense now that I fixed the phase characteristic.

    Thank you anyway.
    Last edited: Jan 18, 2015
  2. jcsd
  3. Jan 18, 2015 #2


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    Staff: Mentor

    No worries! It's always satisfying to sort out a problem yourself.
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