What is the term for the nonlinear relation of input and output induced harmonics in hearing aids?

The term that accurately describes the nonlinear relation of input and output induced harmonics in hearing aids is harmonic distortion. Harmonic distortion occurs when a sound system (like a hearing aid) introduces additional frequencies that are harmonics of the original signal. This results from the imperfections in the signal processing, which can lead to a distortion of the intended sound.

In many audio applications, including hearing aids, the goal is to reproduce sound as accurately as possible. When there is harmonic distortion, it indicates that the hearing aid is altering the original signal in a nonlinear manner, generating additional frequencies that were not present in the original input. This can affect the quality of the sound perceived by the user, making it crucial to minimize harmonic distortion in hearing aids.

Other forms of distortion, like amplitude or phase distortion, refer to different aspects of how the signal may vary with changes in volume (amplitude) or how the timing of the sound signals may be altered (phase). While these types of distortions are relevant in audio engineering, they do not specifically address the harmonics introduced by nonlinearity in the same way harmonic distortion does.