Where can I find a comprehensive explanation of the Filter Design tools available in Matlab?

I have been trying to learn about the filter design tools avaialable in Matlab so that I can make an informed decision about which tools I need to use for particular applications. Unfortunately, I have not found a comprehensive explanation. Instead, I have learned that there appear to be tools in the Signal Processing Tollbox as well as the DSP System toolbox. Some of these tools are GUI-based, and others are functions, but many of them seem to have overlapping features. Both toolboxes appear to have unique data objects for storing filter designs, but I cannot find references to tools for converting between data types. Normally, I use the low-level functions like BUTTER to generate analog or digital filter designs and I will either store these as NUM & DEN arrays or as LTI objects. I also cannot find any reference for how I can convert either NUM,DEN or LTI object formats to any of the unique data objects in the digital filter design/analysis GUI's. This is incredibly confusing and is not what I am used to with regard to traditional MathWorks documentation. Please direct me to a comprehensive reference on all of the digital filter design tools supported by MathWorks. I really hope that I don't have to read all of the documentation for every tool just to figure out which one I need to use...

[dpb]

Good luck on that one...I agree that the "veritable plethora" of competing/overlapping and incompatible toolboxes has become overwhelming. There appear to be no overall design constraints nor master plan but that individual design teams just introduce their own into the wild...

Answer 1

[Abhinav Aravindan]

Hi Steve

I see you are looking for a resource on Filter Design tools and techniques in MATLAB. Here are some key points and resources that may be helpful to you.

1. The Signal Processing Toolbox and DSP System Toolbox are designed for different applications:

• Signal Processing Toolbox: This toolbox is ideal for tasks such as signal analysis and filter design. It includes user-friendly apps like the Signal Analyzer and Filter Designer.
• DSP System Toolbox: This toolbox is tailored for more advanced applications, including real-time DSP systems and adaptive filters.

To better understand the distinctions between these toolboxes, you can refer to these resources:

https://www.mathworks.com/matlabcentral/answers/154274

https://www.mathworks.com/matlabcentral/answers/42887

2. Filter Design Methods: Both toolboxes offer a variety of filter design methods to suit different needs. You can find out a primary list of the filter design methods available in the links below:

https://www.mathworks.com/help/signal/ug/filter-design-methods.html

https://www.mathworks.com/discovery/filter-design.html

3. MATLAB has multiple filter design methods for diverse applications, varying customization and performance needs. For instance, the Butterworth filter can be designed using the following methods

• “butter” function with different parameters
• Filter Designer App
• Filter Builder
• “fdesign”

Each of these methods offers different levels of flexibility and ease of use, hence there is minimal availability of interconversion between different objects. The butter function is suitable for programmatic filter design, while the "Filter Designer" and "Filter Builder" apps provide a visual interface for interactive design. The "fdesign" object offers a more customizable approach for filter design.

https://www.mathworks.com/matlabcentral/answers/522274

Since these are specific to the application, my suggestion is to compare the relevant documentation for your specific requirement.

I hope the above points provide some insight into the available Filter Design Tools in MATLAB!