| 摘要 |
<p>A hearing aid system utilizing digital signal processing is programmable to fit the hearing deficit of a particular user and adaptive to the sound environment to maximize the intelligibility of the desired audio signal relative to noise. A signal picked up from microphone (30) is amplified and filtered by preemphasis circuit (32) and converted to digital data through an 8-bit linear A-to-D converter (47). The processor (50) preferably performs spectral shaping on the data to match the user's preference and performs a non-linear adaptive amplification function on the digital data. The amplification gain function may include several piecewise linear sections, including a first section providing expansion up to a first knee (K1), a second section providing linear amplification from the first to a second knee (K2), and a third section providing compression for signals above the second knee to reduce the effect of over range signals and minimize loudness discomfort to the user.</p> |
