Howtosignalprocessing
- How a band-limited signal can be sampled without aliasing?
- What is aliasing in DFT?
- How aliasing is avoided while taking DFT of a sequence?
- What do you mean by aliasing effect in relation with sampling of analog signals?
How a band-limited signal can be sampled without aliasing?
Thus, band-limited signals can be sampled and fully recovered only when observing the Nyquist criterion. For bandpass signals the Nyquist criterion will ensure no aliasing only when the recovery of the signal is done with a bandpass filter; otherwise a higher sampling frequency will be required.
What is aliasing in DFT?
Usually only a single period of the DTFT is plotted: In other words, when you use a sampling rate of , the frequencies 1 and are indistinguishable. This is called aliasing. In general, the continuous-time frequency is indistinguishable from any other frequency of the form , where is an integer.
How aliasing is avoided while taking DFT of a sequence?
Aliasing is generally avoided by applying low-pass filters or anti-aliasing filters (AAF) to the input signal before sampling and when converting a signal from a higher to a lower sampling rate.
What do you mean by aliasing effect in relation with sampling of analog signals?
The aliasing effect is a measurement error in the signal occurring due to an incorrectly set sampling rate. If the sampling rate is too low, the Nyquist-Shannon sampling theorem is not observed and thus the measurement signal is not acquired correctly.
