摘要 |
A hearing aid (50) comprises means (55, 56, 57, 58) for reproducing frequencies above the upper frequency limit of a hearing impaired user. The hearing aid (50) according to the invention comprises means (55, 57) for transposing higher bands of frequencies from outside the upper frequency lim it of a hearing impaired user down in frequency based on a detected frequency i n order to coincide with a lower band of frequencies within the frequency rang e perceivable by the hearing impaired user. The transposing means (55, 57) comprise an adaptive notch filter (15) for detecting a dominant frequency in the lower band of frequencies, adaptation means (16) controlled by the adaptive notch filter (15), an oscillator (3) controlled by the adaptation means (16), and a multiplier (4) for performing the actual frequency transporting of the signal.
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