Can analog signals be discrete?
Analog signals must be discretized (digitized) to produce a finite set of numbers for computer use. When analog signals are brought into a computer, they must be made discrete (finite and countable). A discrete-time signal is a finite sequence of numbers, with finite possible values for each number.
Is DFT spectrum of a discrete-time sequence periodic?
It has the same sample-values as the original input sequence. The DFT is therefore said to be a frequency domain representation of the original input sequence. If the original sequence spans all the non-zero values of a function, its DTFT is continuous (and periodic), and the DFT provides discrete samples of one cycle.
What kind of signal does complex DFT have?
The complex versions have a complex time domain signal and a complex frequency domain signal. The real versions have a real time domain signal and two real frequency domain signals. Both positive and negative frequencies are used in the complex cases, while only positive frequencies are used for the real transforms.
Which is the family member of the DFT?
The discrete Fourier transform (DFT) is the family member used with digitized signals. This is the first of four chapters on the real DFT , a version of the discrete Fourier transform that uses real numbers to represent the input and output signals.
How are spectrum and spectral density estimation by the discrete Fourier transform?
Spectrum and spectral density estimation by the Discrete Fourier transform (DFT), including a comprehensive list of window functions and some new at-top windows. G. Heinzel, A. Rudiger and R. Schilling, Max-Planck-Institut fur Gravitationsphysik (Albert-Einstein-Institut) Teilinstitut Hannover February 15, 2002
When to use DFT / FFT for spectral density estimation?
G. Heinzel, A. Rudiger and R. Schilling, Max-Planck-Institut fur Gravitationsphysik (Albert-Einstein-Institut) Teilinstitut Hannover February 15, 2002 Abstract This reporttriesto givea practicaloverviewaboutthe estimationof powerspectra/power spectral densities using the DFT/FFT.