Transfer function from a frequency response graph
显示 更早的评论
I want to know if exist some MATLAB function that can give me a transfer function by analysis from points of a frequency response graph
回答（2 个）
Arkadiy Turevskiy
2012-8-22
编辑：Arkadiy Turevskiy
2018-12-19
1 个投票
System Identification Toolbox is an add-on to MATLAB for estimating transfer functions as well as other model types from time or frequency domain data.
You can estimate a transfer function from frequency domain data using the function tfest from this toolbox.
Here is a demo that might be helpful. The demo is using ssest for estimating state-space models, but you can definitely use tfest instead for estimating a transfer function.
HTH.
Arkadiy
1 个评论
Shmuel Nedjar
2017-7-10
Thank you for your helpful answer, suggesting functions from the System Identification Toolbox. I was unaware of such a toolbox and appropriate functions for accomplishing this task. CJL
Azzi Abdelmalek
2012-8-14
0 个投票
i suggest:
- from your frequency response, calculate a temporel pulse response h(t) (it's the inverse Fourier transform of your frequency response
- choose a white band signal x(t), and calculate y(t)=x(t)*h(t) (* is convolution).
- from x and y identify your transfer function (you must know the order of your system which is given by your frequency response)
5 个评论
Rodrigo Trigona
2012-8-14
Azzi Abdelmalek
2012-8-14
if your system is linear, if H(w) is your frequency response,
- plot 20*Log10(H(w)) with log axis (bode diagram)
- if the drop in db is 20*n then your order system is n
Star Strider
2012-8-14
You have to have both the amplitude and phase information for your system. If you only have the amplitude, you have only half the information you need to reconstruct your system.
Azzi Abdelmalek
2012-8-14
when he said frequency response , that means amplitude and phase
Star Strider
2012-8-15
True, but we don't know exactly what he has, or what information he can recover from the graph. My intent in my previous comment was to find that out.
类别
在 帮助中心 和 File Exchange 中查找有关 Linear Model Identification 的更多信息
2012-8-14
2018-12-19
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
