# How to graph a bode plot with a quadratic pole?

Discussion in 'Homework Help' started by TripleDeuce, Feb 6, 2011.

1. ### TripleDeuce Thread Starter New Member

Sep 20, 2010
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How do I graph this transfer function?

H(ω) = j40ω(1+jω/10) / [1-(ω/50)^2+jω/125]

I can graph the numerator part, but how do I graph the magnitude and phase angle plots of the denominator?

2. ### hgmjr Retired Moderator

Jan 28, 2005
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First you must factor the denominator into the two disctinct poles?

hgmjr

Nov 25, 2009
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4. ### The Electrician AAC Fanatic!

Oct 9, 2007
2,621
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You haven't said that you must graph it by hand. If that's not the case, then plotting a transfer function is simple, what with all the software available today.

If you are required to plot it by hand, then you should say so. If that is the case then you must find the roots of the denominator; they are the poles of the transfer function.

Attached is a plot done with typical mathematical software.

The first plot shows the magnitude of the numerator, denominator and overall transfer function.

The second plot shows the phase of the overall transfer function.

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