I have a signal and I'm interested in identifying the dominant frequencies greater than 1/3600 Hz. To do this, I use Fast Fourier Transforms and examine the locations of the peaks in the frequency domain, which reveals that the largest peaks are below this frequency. As a noob, it seems like there are two potential options:
- Simply ignore the FFT results outside my desired range and focus on my region of interest.
- Filter the signal (e.g., with a Butterworth high-pass filter) before I perform the FFT.
What are the pros and cons of these approaches? Is there a third (or fourth, fifth, sixth...) option that is better than both of these methods at achieving my goal?