Best way to do accurate amplitude measurements using FFT

1. How can I make my FFT more accurate?
2. How do you calculate amplitude from FFT?
3. How do you normalize FFT amplitude?
4. How accurate is FFT?

How can I make my FFT more accurate?

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.

How do you calculate amplitude from FFT?

1) Division by N: amplitude = abs(fft (signal)/N), where "N" is the signal length; 2) Multiplication by 2: amplitude = 2*abs(fft(signal)/N; 3) Division by N/2: amplitude: abs(fft (signal)./N/2);

How do you normalize FFT amplitude?

Normalise the fft by dividing it by the length of the original signal in the time domain. Zero values within the signal are considered to be part of the signal, so 'non-zero samples' is inappropriate. The length to use to normalise the signal is the length before adding zero-padding.

How accurate is FFT?

Discrete Fourier transforms computed through the FFT are far more accurate than slow transforms, and convolutions computed via FFT are far more accurate than the direct results. However, these results depend critically on the accuracy of the FFT software employed, which should generally be considered suspect.