Signal in frequency domain with OpenCV dft

1. What is DFT in frequency domain?
2. How do I get DFT frequencies?
3. Which property of DFT provides energy of signal in time and frequency domain?
4. What is frequency analysis using DFT?

What is DFT in frequency domain?

In mathematics, the discrete Fourier transform (DFT) converts a finite sequence of equally-spaced samples of a function into a same-length sequence of equally-spaced samples of the discrete-time Fourier transform (DTFT), which is a complex-valued function of frequency.

How do I get DFT frequencies?

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.

Which property of DFT provides energy of signal in time and frequency domain?

Periodicity property of DFT in time and frequency domain.

What is frequency analysis using DFT?

Abstract: The analysis of arbitrary time samples of signals of interest in terms of a Fourier series in effect forces the signal to be periodic with a fundamental period equal to the sample length.