Popular Science: What is the principle of hearing aid intelligent tracking to reduce noise?

In the process of using hearing aids in the past, when we talk softly, we always feel that the background noise in the environment is also amplified at the same time, so that the speech signal of soft talk is not very clear; or, when the user of the hearing aid is driving a car When you open the car windows at the same time, the wind outside will become particularly loud.Now with hearing aids to the newly researched “adaptive noise management system”, it can better improve the hearing of hearing aid wearers in noisy environments. The “Adaptive Noise Management System” performs real-time evaluation of the sound signals entering the hearing aid: the input signal related to the language changes randomly, because when we speak, the voice is up and down, the instantaneous waveform of the speech spectrum is very different, and the standard deviation is also very large. Large; while the input signal related to noise is stable and continuous, the waveform is relatively stable, and the standard deviation is small.


Noise has always been a big problem in wearing. How to improve the performance of hearing aids in noisy environments has always been a key research direction of hearing aid companies.In recent years, many new technologies have emerged in the hearing aid industry. Microphone noise suppression, directional technology, digital noise suppression, speech enhancement, wind suppression, feedback suppression and instantaneous noise tracking are all dedicated to improving the performance of hearing aids under noise.

Case:

The neighbor’s mother-in-law Li is over 60 years old and suffers from moderate to severeHearing loss, She is often difficult to communicate with others because she can’t hear the words clearly.She has chosen a few times Hearing aid , But every time she wears it for a period of time, she encounters such a problem: when she wears a hearing aid to the street and communicates with multiple people at the same time, it is difficult for her to distinguish which sentence is said by which person.These unintelligible voices were mixed together, turning around her ears like a mess, which made her very painful.
The “automatic noise tracking” process will evaluate the sound signal entering the hearing aid: the input signal changes randomly (related to language), when we speak with different emotions, it is circumflex, and the instantaneous waveform of the speech is rapidly changing, the standard The deviation is large, so the ratio of the voice amplitude to the standard deviation (deviation rate) is small; the input signal is stable and continuous (related to noise), the noise waveform is relatively stable, and the standard deviation is small, so the ratio of the noise amplitude to the standard deviation (deviation rate) ) Is larger.

The technology of hearing aids to achieve low-distortion and other hearing-aid effects.

We all know that sound is produced by the vibration of an object, and the object that is making a sound is called the sound source.It is transmitted in the form of sound waves.It is reported that the hearing aid manufacturer adopts self-developed aerospace-level intelligent active noise reduction technology to start from the source of the sound and actively counter and eliminate the existing noise!The noise reduction process is as follows: the high-sensitivity microphone built into the hearing aid is used as a sensor to detect and collect sound signals in the environment, and pass them back to the CAS863A noise reduction chip circuit system. The system analyzes the collected sound signals through a huge voiceprint library In contrast, the noise and the main sound are intelligently separated (to judge whether it is a sound or a noise), the separation is completed, and a real-time operation generates a set of sound waves with the same amplitude and opposite phase as the noise signal, which neutralizes the noise and achieves the purpose of noise reduction for hearing aids, namely filtering Environmental noise.

In general, this new noise reduction concept hearing aid uses intelligent active noise reduction technology to deal with environmental noise, which is the first in the hearing aid industry, opening up a new noise reduction processing method for hearing aids, and redefining The natural and clear sound quality of hearing aids is undoubtedly a great boon for hearing impaired patients.

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