Hearing aidWhat is the history of development?
With the accelerated pace of life, increased pressure on life, increased industrial noise, and serious phenomena in the elderly, the number of people with hearing loss is growing. At present, the hearing-impaired population in China has more than2780Million. With the improvement of people’s living standards and the popularity of health awareness, more and more customers need the assistance of hearing aids.
Hearing aidHas a long history of development, early in the20In the century, electric amplified hearing aids appeared. With the development of signal processing technology, hearing aids have become smaller and smaller, from the cassette machine to the in-ear machine, super invisible, and more and more compact. In addition, in order to meet the needs of various users, the technology of hearing aids has developed rapidly. From peak clipping technology, push-out circuit, automatic gain control technology, and multi-mike technology, we have provided more selective space.
In the early days of our life, we invented the sound collector.19In the century, ear horns, talking tubes and horns of various shapes and sizes have appeared. These are mainly to use a large mouth to accept the sound, increasing the sound level of the local speech band. But carrying it is not very convenient.
To20At the beginning of the century, carbon hearing aids appeared. It can be conveniently carried, mainly using carbon microphones and magnetic headphones to achieve sound wave propagation. However, there are more noises and distortions.
1921The first tube produced in the UKHearing aid, it requires the supply of two power supplies,AThe voltage of the power source is low, and the filament in the electron tube is heated to discharge it;BThe power supply voltage is relatively high and the drive electronics reach the anode. The voltage of the microphone controls the fluctuation of the larger current.
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