Bode plot

Discussion in 'Homework Help' started by markmc001, Apr 26, 2009.

  1. markmc001

    Thread Starter Member

    Mar 10, 2008
    12
    0
    Hi all,
    I have some questions to answer for my HNC homework, but am having a little trouble understanding the example we were given. I have top draw out some asymptotic bode diagrams.

    In the example given the bode diagram was derived from the following formula:
    Vo / Vin (jω) = 3 / (1+j3ω)(1+j4ω)

    I know that the break points are at 0.25 and 0.33 as these can be found by inverting the constants 3 and 4, but I am not sure how to find the start point, which in this case is 9.5dB.

    Any help would be much appreciated.
    Mark
     
  2. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    The formula you need to apply is:

    Gain_{(dB)}\large\ =\ 20*log_{10}(3)

    The 3 used above is the voltage gain taken from the transfer function.

    hgmjr
     
    Last edited: Apr 26, 2009
  3. markmc001

    Thread Starter Member

    Mar 10, 2008
    12
    0
    Thats great. That should get me started. Thanks for your help.
    MM
     
  4. Ron H

    AAC Fanatic!

    Apr 14, 2005
    7,050
    656
    The reason for this is that when ω=0 (DC), the numerator is 1.
     
Loading...