What is Aliasing?

Aliasing is an error in digital signal processing where a signal appears to be completely different (lower frequency) than it actually is because it was sampled too slowly. The "wagon-wheel effect" in movies, where car wheels appear to spin backwards, is a visual example of aliasing.

Technical Explanation

According to the Nyquist Theorem, to measure a signal correctly, you must sample at a rate at least twice the highest frequency of that signal.

If you sample a 50Hz vibration at 60Hz, you will see a "ghost" signal at 10Hz. This signal does not exist in reality; it is a mathematical error.

ZMA Data Acquisition modules have a sampling rate of 1000Hz (1kHz). This allows you to safely capture dynamic events and vibrations up to 500Hz without falling victim to aliasing errors.