Aliasing is a term generally used in the field of digital signal processing. When an analog signal is digitized, any component of the signal that is above one-half the sampling or digitizing frequency will be 'aliased.

Why is aliasing used?

Sometimes aliasing is used intentionally on signals with no low-frequency content, called bandpass signals. Undersampling, which creates low-frequency aliases, can produce the same result, with less effort, as frequency-shifting the signal to lower frequencies before sampling at the lower rate.

What is aliasing give an example?

Aliasing: Aliasing refers to the situation where the same memory location can be accessed using different names. For Example, if a function takes two pointers A and B which have the same value, then the name A[0] aliases the name B[0] i.e., we say the pointers A and B alias each other.