د/ايمان زغلول قاسم

استاذ تكنولوجيا التعليم المساعد بكلية التربية بالزلفي

تقنية لينك ات

Link–IT

– Nan Asher

Link–IT is an array microphone system designed to improve listening in noisy situations. It is developed by Etymotic Research.

Photo of Link–IT.

Link–IT stands for “Link in T–coil. ” This is an assistive listening device used with a hearing aid or cochlear implant to improve speech intelligibility in noisy situations. The Link–IT contains a three–microphone array, which gives a 7–10 dB noise reduction. The Link–IT transmits its signal to the t–coil in the hearing aid or cochlear implant receiver. It is compatible with hearing aids and cochlear implant receivers that have a built–in t–coil (telecoil).

The microphone array only permits sound to be received from in front of the wearer. Background sounds coming from the rear or sides are suppressed. The microphones are placed in a straight line. A sound wave coming from the front will have a different arrival time than sounds coming from the sides and rear. Each microphone signal is delayed relative to the adjacent one. The microphone signals are then summed, resulting in a high output signal. A sound wave coming from the side arrives simultaneously at each side microphone, but each microphone signal is delayed differently, resulting in a low output signal.

Photo of Link–IT.

The Link–IT uses an induction signal to provide a connection to the hearing aid. Link–IT is designed to be used when directional hearing aids do not provide sufficient directivity, or with hearing aids or cochlear implant devises that do not have directional microphone capability. Link–IT is especially effective in noisy, reverberant areas, such as restaurants or parties, where speech understanding is difficult even for those with normal hearing.

Two Link–ITs worn with two aids may provide stereo sound. Link–IT can replace FM systems in certain situations. A binaural (two aid) fitting gives approximately 2–3 dB additional improvement in SNR compared to a monaural (one aid) fitting. With two Link–ITs, the user has true binaural processing (whereas most other systems transmit the same signal to both ears.) However, most users opt to turn off one aid, and use the other with the Link–IT.

To down load a brochure about Link–IT:
http://www.etymotic.com/pdf/linkit-brochure.pdf