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Concept# Noise

Summary

Noise is unwanted sound considered unpleasant, loud, or disruptive to hearing. From a physics standpoint, there is no distinction between noise and desired sound, as both are vibrations through a medium, such as air or water. The difference arises when the brain receives and perceives a sound.
Acoustic noise is any sound in the acoustic domain, either deliberate (e.g., music or speech) or unintended. In contrast, noise in electronics may not be audible to the human ear and may require instruments for detection.
In audio engineering, noise can refer to the unwanted residual electronic noise signal that gives rise to acoustic noise heard as a hiss. This signal noise is commonly measured using A-weighting or ITU-R 468 weighting.
In experimental sciences, noise can refer to any random fluctuations of data that hinders perception of a signal.
Measurement
Sound is measured based on the amplitude and frequency of a sound wave. Amplitude measures how forceful the wave is. The

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Acoustic noise is present in many environments. Such noise is undesirable and provides a poor listening experience. Active noise cancellation refers to the fact of reducing undesired noise using a cancelling signal emitted trough a secondary source. Many methods are proposed to perform active noise cancellation on headphones. In this work, we are interested in performing digital active noise cancellation for a wearable device. There are many challenges for such a system. The noise cancellation process has to be performed in real time therefore as fast as possible. Besides, all the operations of such a system has to be digitally processed. Therefore, one of the most important points is to evaluate the performance of the different methods and algorithms needed for performing digital active noise cancellation on real time.

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