How to do high-resolution FFT on just the lower frequencies in a signal?

1. How do I increase the resolution of my FFT?
2. What is frequency resolution of FFT?
3. What is the minimum number of samples for fast Fourier transformation?
4. How does sampling frequency affect FFT?

How do I increase the resolution of my FFT?

The most intuitive way to increase the frequency resolution of an FFT is to increase the size while keeping the sampling frequency constant. Doing this will increase the number of frequency bins that are created, decreasing the frequency difference between each.

What is frequency resolution of FFT?

Frequency resolution is 10 Hz. The time waveform with length of 0.1 seconds is used for an FFT analysis. The spectrum values are obtained by performing FFT every 10 Hz. The spectrum cannot be obtained with the fractional frequency component values, such as 995, 1001 Hz.

What is the minimum number of samples for fast Fourier transformation?

The fast Fourier transform (FFT) is a computer algorithm developed by James Cooley and John Tukey. The algorithm computes the coefficients for the Fourier series that represents a sequence. The number of samples (N) in the FFT must be an integer power of 2.

How does sampling frequency affect FFT?

The amplitude of the DFT (FFT) is proportional to the number of samples. Therefore, if you sample for twice as long at the same sampling frequency, or if you sample for the same duraiton but twice as fast, you will have twice as many data points, and the DFT amplitude will be twice as large. See examples below.