Howtosignalprocessing
- How do you calculate DFT frequency?
- What is sampling frequency in DFT?
- What is the frequency spacing between the spectral samples?
- How does the length of a signal affect the DFT?
How do you calculate DFT frequency?
calculate the magnitude of each DFT output bin: magnitude = sqrt(re*re+im*im) find the bin with the largest magnitude, call its index i_max . calculate the equivalent frequency of this bin: freq = i_max * Fs / N , here Fs = sample rate (Hz) and N = no of points in FFT.
What is sampling frequency in DFT?
Data are sampled discretely at a sampling frequency of 0.5 Hz. Starting at time t = 0, N = 4 data points are taken. Here, T = 8 s, Δt = T/N = (8 s)/4 = 2 s, and fs = 1/Δt = 0.5 Hz. The discrete data used to calculate the DFT are those at t = 0, 2, 4, and 6 seconds.
What is the frequency spacing between the spectral samples?
The eight frequency domain spectral lines are spread evenly between 0 and 16 Hertz, which results in the 2.0 Hertz spacing on the frequency axis.
How does the length of a signal affect the DFT?
The length N of the DFT is the number of frequency points that will result in the DFT output. Zero padding will result in more frequency samples, however this does not increase frequency resolution, it just interpolates samples in the DTFT.
