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03-15-2021
09:10 AM

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03-15-2021
09:10 AM

Need help with plotting column matrix for bode plot

Hi all,

I hope everyone is having a great day!

I am trying to plot a bode plot(i.e gain in dB w.r.t w in rads-1) at specific frequencies inputted in a vector/matrix.

How then do I plot the column matrix('gaindB') with w(rad s-1) on the horizontal axis?

The transfer function is given by f(s) where s represents laplace constant of j*w

I have attached my workings below.

Solved! Go to Solution.

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1 ACCEPTED SOLUTION

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03-17-2021
10:31 AM

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03-17-2021
10:31 AM

You have to vectorize your expressions (put an arrow above it, look that up in the 'Operators' section on the Math ribbon. It's in the lower-right corner:

I'll leave the phase to you..

The table is easy to reproduce except for the argument at w=0.8. Note that the phase runs on negative continuously, but the argument of a complex number is generally limited to between -pi and pi, or -180 deg and 180 deg.

Success!

Luc

16 REPLIES 16

03-15-2021
09:40 AM

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03-15-2021
09:40 AM

Because gaindB is a vector taking the magnitude results in a scalar. Vectorize:

03-16-2021
04:39 AM

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03-16-2021
04:39 AM

The numeric value on the right-hand side of each equation is substituted for the name on the left-hand side in the expressions that define the model. No checking is done during the substitution to determine whether the substituted value is valid.

03-16-2021
07:27 AM

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03-16-2021
07:27 AM

Look up vectorize

03-17-2021
08:44 PM

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03-17-2021
08:44 PM

You are replying to a SPAM posting 😉

The text was copied from here: https://de.maplesoft.com/support/help/maple/view.aspx?path=DynamicSystems%2FResponsePlot

The text should look innocent and appropriate for the forum at first glance and when after a while the posting has passed moderation, a SPAM-Link is added. Unfortunately a quite common method which can be seen on other forums as well.

03-18-2021
09:20 AM

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03-18-2021
09:20 AM

Thanks for the tip!

I rarely chase links in these posts; if there isn't a file attached, or at least a picture, they aren't serious. (And Malwarebytes has been very good at issuing warnings!)

03-18-2021
10:06 AM

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03-18-2021
10:06 AM

what sorry?

03-18-2021
04:58 PM

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03-18-2021
04:58 PM

That's not about your post, but the one from LS_9861888.

Luc

03-16-2021
02:30 PM

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03-16-2021
02:41 PM

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03-16-2021
02:41 PM

How to put grid in the graph in Mathcad Prime for Bode Plot (Magnitude & Phase Plot's)?

Or is it only possible if we use a chart component or something like that?

03-16-2021
02:52 PM

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03-16-2021
02:52 PM

The standard plot of Prime does not come with grids, but there are several methods to put in a grid.

The 3rd party add-on chart-component does provide grids, but it doesn't deal properly with units (as far as I know).

Here's the result of my grid routine

Success!

Luc

03-17-2021
09:25 AM

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03-17-2021
09:25 AM

Hi Lucmeekes,

Thanks for that! I am looking at the file you attached.

Can you help me calculate the complex numbers for the specific frequencies in the 'w' vector? The file attached below has wrong values. However, in the bode plot you have plotted does do it correctly, I just need the complex numbers(Re and Im parts) and the gain(screenshot 227). How can I do this, I used vector 'w' but it does not work?

Of course this can be done by pen and paper but that will take too long.

03-17-2021
10:31 AM

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03-17-2021
10:31 AM

You have to vectorize your expressions (put an arrow above it, look that up in the 'Operators' section on the Math ribbon. It's in the lower-right corner:

I'll leave the phase to you..

The table is easy to reproduce except for the argument at w=0.8. Note that the phase runs on negative continuously, but the argument of a complex number is generally limited to between -pi and pi, or -180 deg and 180 deg.

Success!

Luc

03-18-2021
04:22 PM

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03-18-2021
04:22 PM

Why do we need to vectorize the h transfer function?

03-18-2021
04:43 PM

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03-18-2021
04:43 PM

Is it possible to increase the thickness of the numbers on the two axes (values on the x and y axis) in the XY plot? Or this thing is possible just in the Chart Component?

03-18-2021
05:14 PM

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03-18-2021
05:14 PM

So far I have not found any settings to control the axis colour.

Luc

03-18-2021
05:13 PM

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03-18-2021
05:13 PM

We need to vectorize because f is a vector. You're plotting the same transfer function with respect to the variable freq. Now freq is undefined (you didn't define it before the plot) so Prime uses it as an automatic variable, and defines it as a range (that is something different from a vector ! ). While it is handy sometimes for plotting, this automatic variable is not well under your control.

Success!

Luc