- #1
Melawrghk
- 145
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Homework Statement
I'm doing a question that requires a Bode plot (magnitude and phase).
The Attempt at a Solution
I got a transfer function of
[tex]H(\omega)=\frac{1+\frac{j*\omega}{3}}{1-0.1667(\omega)^{2}+0.4167j*\omega}[/tex]
So there is a simple zero at 3 rad/s; complex pole at 2.45 rad/s; and no DC gain.
I am able to plot the magnitude plot correctly, however my phase isn't exactly right.
For phase I have essentially two contributions from the zero and the pole:
From zero: 0.3<omega<30 rad/s with a slope of 45 degrees/decade
From pole: 0.245<omega<24.5 rad/s with a slope of -90 degrees/decade
So combining the two, I get (w==omega, I'm too lazy to write it out):
0<w<0.245: 0 degrees,
0.245<w<0.3: slope of -90 degrees/decade
0.3<w<24.5: slope of -45 degrees/decade
24.5<w<30: slope of 45 degrees/decade
w>30: slope of 0
However the solution my prof provided says:
0<w<0.245: 0 degrees,
0.245<w<0.3: slope of -90 degrees/decade
0.3<w<24.5: slope of -45 degrees/decade
w>24.5: slope of 0, flattens out at -90 degrees.
Am I wrong? If so, why?