Plotting bode diagram with a transfer function without values

Hi, I'm pretty new at MATLAB and I am trying to plot a bode with a transfer function of J*W*L / (R + J*W*L) without any values. Is this possible? Thank you in advance!

Answer 1

[Star Strider]

No.

How would you plot it without assigning values to any of the varaibles? (It would be possible to symblically derive some characteristics (half-power point and perhaps some others, since there are no capacitors there is no resonant frequency to be calculated), however those remain symbolic until values are assigned.

MATLAB has the same problem.

[Luc Momber]

Am I understanding this question wrong then? I'm pretty sure that exercise E is right, so how could it be possible to solve exercise F then?

Thank you for your quick response

[Star Strider]

Assuming that the mains power frequency is 50 Hz, it would be necessary to design the filter to have a half-power point (stopband) frequency of 50 Hz or so. (I initially thought that this was part of a power supply, however I now see that it is part of an audio output circuit.) That is dictated by the available components and chassis form-factor, however in my experience having the inductive impedance (apparently reactance because the internal resistance of the inductor is neglected here) and the value of the resistance to be about the same at 50 Hz (or 60 Hz depending on the local mains power frequency) would produce a circuit with the greatest stability. So I would calculate the value of ‘L’ depending on the reactance at the cutoff frequency, and match ‘R’ to it. This will likely require some experimentation.

This would be my design approach, however it will be necessary for you to use the design approach your instructor would expect.

[Luc Momber]

thank you for your answer. If you are curious, with help of my instructor I found out that the searched for answer is this:

Thank you much for your time!

[Star Strider]

As always, my pleasure!

I have no idea what the context of the exercise is.

tf_variable = tf([1 0],[1 1])

tf_variable =
 
    s
  -----
  s + 1
 
Continuous-time transfer function.

figure
bodeplot(tf_variable)
grid

.