Designing a band-stop FIR filter

Thread Starter

Jack Tranckle

Joined Jan 20, 2016
I am wanting to design an FIR band stop filter, it is a bit of a project that I found for me to learn Matlab.

These are the given specs:

Sampling frequency: 5 kHz
Pass-band ripple/deviations: ≤ 2 dB
Stop-band attenuation: ≥ 40 dB
Lower pass-band edge frequency: 500 Hz
Lower stop-band edge frequency: 800 Hz
Upper stop-band edge frequency: 1200 Hz
Upper pass-band edge frequency: 1500 H

I have sketched a graph by hand, but am wanting to understand that this is done in Matlab? also, how do you calculate the coefficient ?

how can I design it using the window method, or the optimal method? any help is greatly appreciated. Thanks!


Joined Nov 6, 2017
A couple of questions:
- do you want to do this "from scratch" or by using Matlab's filter design features (e.g. filter design toolbox or firls, etc)?
- what toolboxes do you have - all Matlab toolboxes, including filter design toolbox?

If you launch the filter design toolbox, it simply becomes an exercise in exploration. If you use firls, you simply need to understand the documentation. Doing it from scratch gets a bit more involved, but it gives more control and down-in-the-dirt understanding that you only get from working in the kitchen, though it also has stronger prerequisites on DSP knowledge.