Aliasing and folding

1. What is folding and aliasing?
2. What is folding in sampling?
3. What is aliasing in sampling?
4. What is the meaning of aliasing?

What is folding and aliasing?

Spectral Aliasing (Figure 1) and Folding (Figure 2) are phenomena in which NMR peaks occur at frequencies that are different from their real frequencies. Such peaks are called folded or aliased peaks, depending on the applied method of data acquisition.

What is folding in sampling?

In signal processing, the Nyquist frequency (or folding frequency), named after Harry Nyquist, is a characteristic of a sampler, which converts a continuous function or signal into a discrete sequence. In units of Hz (cycles per second), its value is one-half of the sampling rate (samples per second).

What is aliasing in sampling?

Aliasing occurs when an oscilloscope does not sample the signal fast enough to construct an accurate waveform record. The signal frequency is misidentified, and the waveforms displayed on an oscilloscope become indistinguishable. Aliasing is basically a form of undersampling.

What is the meaning of aliasing?

noun. ali·​as·​ing ˈā-lē-ə-siŋ ˈāl-yə- : an error or distortion created in a digital image that usually appears as a jagged outline. We commonly observe aliasing on television.