How to construct asymptotic bode plot in a more automatical way?

Forum|Forum|1 year ago
July 5, 2024
2 replies
5717 views

Hi,

How can I draw the ASYMPTOTIC bode plot of this function in more automatical way? Is it possible? I mean I know that this asymptotic bode plot can be draw after some manual analysis, but is it possible to make a program that can draw automatically this thing?

I am expecting something like that (red plot):

1_asymptotic-bode-plot.zip

Best answer by LucMeekes

So, after some fumbling I was able to improve the automatic asymptote generation for bode plots.

The function should work fine for most real-world examples of filters,

as an example:

or, another example:

The option to supply H as a 2-column vector should work well if you import data from a circuit simulation program (Spice) to plot.

See attached file, which also works in Prime express. (Yes, all it took was a one-liner.)

Success!
Luc

W

Werner_E

25-Diamond I

@Cornel wrote:

Hi,

How can I draw the ASYMPTOTIC bode plot of this function in more automatical way? Is it possible? I mean I know that this asymptotic bode plot can be draw after some manual analysis, but is it possible to make a program that can draw automatically this thing?

Depending on those "some manual analysis" it may be possible to turn exactly those calculation into a program.

BTW, the third argument of the "logspace" function is dimensionless, its the number of entries created. I wonder why Prime does not throw an error when you chose 800 Hz as argument but rather seems to simply ignore the unit.

C

Cornel

Author

19-Tanzanite

I see that Matlab has some function that can do this:
https://www.mathworks.com/matlabcentral/fileexchange/97627-asymptotic-bode-diagrams-extended?s_tid=FX_rc3_behav

W

Werner_E

25-Diamond I

@Cornel wrote:

I see that Matlab has some function that can do this:

So you should rather use Matlab instead of Mathcad for your tasks.

Matlab has a wealth of features and capabilities that Mathcad lacks.

Here is a bold attempt done with Mathcad. Sure not generic and not a 1-button-push solution.
You may use it as a starting point for your own attempts.