How to make a bandpass filter to only let 1-2 Hz of our signal pass?

I'm trying to make a bandpass filter for a signal so I can find the single frequency when I take the fourier transform of the signal. I only want frequencies between 1-2 Hz.

[Jan]

What have you tried so far? Which problem do you have?

Answer 1

[Star Strider]

If you have R2018a or later, use the bandpass (link) function. It designs an efficient elliptical filter.

If you use the second ‘d’ (digital filter object) output, use filtfilt to filter your signal with it, not filter as in the documentation.