# Plot the asymptotes on a bode diagram of any transfer function

**URL:** <https://discourse.julialang.org/t/plot-the-asymptotes-on-a-bode-diagram-of-any-transfer-function/107143>\
**Category:** Modelling & Simulations\
**Tags:** package\
**Created:** [December 5, 2023, 4:54am UTC](https://discourse.julialang.org/t/plot-the-asymptotes-on-a-bode-diagram-of-any-transfer-function/107143 "2023-12-05T04:54:44Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Frederic\_Gilt](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/frederic_gilt/32/13807_2.png) [@Frederic\_Gilt](https://discourse.julialang.org/u/Frederic_Gilt)\
**Post date:** [December 5, 2023, 4:54am UTC](https://discourse.julialang.org/t/plot-the-asymptotes-on-a-bode-diagram-of-any-transfer-function/107143/1 "2023-12-05T04:54:44Z")

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My question is in the title :). I used ControlSystems package but wasn’t able to find a clean way to plot those asymptotes, and didn’t find any related topics here… Do I need to built it from scratch ? Thx for the help !

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**Author:** ![baggepinnen](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/baggepinnen/32/693_2.png) [@baggepinnen](https://discourse.julialang.org/u/baggepinnen)\
**Post date:** [December 5, 2023, 2:01pm UTC](https://discourse.julialang.org/t/plot-the-asymptotes-on-a-bode-diagram-of-any-transfer-function/107143/2 "2023-12-05T14:01:27Z")

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ControlSystems.jl does not contain any functionality to plot asymptotes. It sounds like a hard problem to solve well in general, unless you want the 0 \leftarrow and \rightarrow \infty asymptotes for simple systems only. For example, what do you draw for

\dfrac{1}{(s + 1) (s + 100)}

? Do you draw the line between 1 and 100, or only the lines from 100 and upwards and 1 and downwards?

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**Author:** ![Frederic\_Gilt](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/frederic_gilt/32/13807_2.png) [@Frederic\_Gilt](https://discourse.julialang.org/u/Frederic_Gilt)\
**Post date:** [December 6, 2023, 12:25am UTC](https://discourse.julialang.org/t/plot-the-asymptotes-on-a-bode-diagram-of-any-transfer-function/107143/3 "2023-12-06T00:25:47Z")

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Thanks for your comment, usually we break down the transfer function (here 1/(s+1) \* 1/(s+100)) then place the natural frequencies on the graph and start drawing pole by pole, finally we redraw the whole response. ControlSystems is capable of providing poles, so I assume that by following the above steps it’s possible to reach the asymptotic response. I’ve got a bit of time now, so I’ll try to come up with something (with my humble level of Julia programming :). There’s a nice (French) lesson on youtube about this, and they use their transfer function as an example: H(p)=\frac{10.(1+0.5p)}{p.(1+p).(1+0.05.p)}. Will take it as exemple