What is aliasing artifacts?

Aliasing artifacts are a common problem in digital signal processing (DSP) when the frequency of a signal is too high for the sampling rate of a DSP system. When this happens, high-frequency content in the signal will be "aliased" or folded back into lower frequencies, causing distortion in the signal.

One common type of aliasing artifact is known as the "foldover distortion," which refers to the appearance of spurious signals in a frequency spectrum when the highest frequency of a signal is less than half the sampling rate. These spurious signals appear as copies of the true signal, but they are shifted in frequency by multiples of the sampling rate.

Another type of aliasing artifact is phase distortion, where the phase of the signal is affected in a non-linear way due to aliasing. This can cause the signal to sound "warbly" or "pulsing."

To prevent aliasing artifacts, it is important to apply a low-pass filter to the signal before sampling it. This will prevent any high-frequency content from being aliased, and will ensure that the digitized signal is a faithful representation of the original analog signal.