Aliasing and square waves

1. What is aliasing in EEG?
2. What causes aliasing?
3. What is aliasing in sampling theory?
4. What is aliasing in vibration?

What is aliasing in EEG?

Aliasing is the generation of false data through inadequate sampling rates in the process of analog-to-digital conversion. At least two different forms of aliasing have been described in quantitative EEG (QEEG) analysis.

What causes aliasing?

Answer : 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 aliasing in sampling theory?

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.

What is aliasing in vibration?

This phenomenon of formation of a lower-frequency wave due to under sampling is called aliasing. All data collectors/analyzers have automatically selected built-in sampling rates to ensure that no aliasing occurs. In theory, there should be no vibrations with frequencies of more than half of this sampling rate.