How to make a bode plot from a transfer function

Forum|Forum|5 years ago
November 9, 2020
2 replies
10163 views

Hello guys,

please help me to solve this problem.

I would like to plot the magnitude and phase over a logarithmic frequency axis for a given transfer function.

In the first picture I create the transfer function with symbolic mathematics.

In the second picture I declare some parameters (but without units !) and I tried to plot the magnitude ...

The single point in the graph is unclear to me with a value of approx. 20 ?? All the values on the y-axis must be < 1 ... or < 0db

Thanks in advance

Electrical_Engineering

L

LucMeekes

23-Emerald IV

Please attach your Prime worksheet, not just a picture!

It will help us to help you in the best way.

Success!
Luc

X

xyz123

Author

12-Amethyst

Hello guys,

@LucMeekes :

I did not upload my sheet because I know there are compability problems with different mathcad-versions. I am using mathcad prime 3.0

Anyway, I attached my sheet, I hope it helps!

@Fred_Kohlhepp:

Unfortunately it didnt work ... , but good idea with the variable i - in my case k -

Since s = 2*pi*k* I also dont like the steps with 2*pi = approx. 6Hz ...

How would you scale the steps of the x-axis to 1Hz, 2Hz, 3Hz, ...

Or even better: How do I scale the x-axis logarithmically? In that case the steps would be 1Hz, 10Hz, 100Hz, 1kHz, ...

Thanks in advance and best regards,

Dimitri

1_Frage_Forum.zip

F

Fred_Kohlhepp

23-Emerald I

The attached pdf was created in Prime 4.0 Express. Since you're using 3.0, the Mathcad file won't do much, but you can type the expressions--they should run in 3.0. (The grid plot is a special, not part of what PTC sells, but you can have a logarithmic scale from the plot menu.

1_Bode-tutorial.pdf

2_Bode-tutorial.zip