Time domain aliasing in dft

1. What is time domain aliasing?
2. What is aliasing in DFT?
3. What is aliasing in frequency domain?
4. How aliasing is avoided while taking DFT of a sequence?

What is time domain aliasing?

Aliasing is usually used as a negative term to indicate this type of overlapping that occurs on an ADC if you don't filter out the frequencies above the Nyquist rate, but aliasing is really a general term for frequencies that are the sampling rate apart being identical to each other when in the digital domain because ...

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.

What is aliasing in frequency domain?

Aliasing is the effect of new frequencies appearing in the sampled signal after reconstruction, that were not present in the original signal. It is caused by too low sample rate for sampling a particular signal or too high frequencies present in the signal for a particular sample rate.

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.