| 摘要 |
<p>An active noise reduction (ANR) arrangement for reducing acoustic noise in an earphone structure (1) includes an automatic gain control arrangement (14-20) providing a variable loop gain dependent upon the variable noise reduction which is produced in the earphone (1) by the active noise reduction arrangement and which is effectively measured by noise pick-up microphones (5 and 13) located, respectively, in earphone structure front and rear internal cavities (11 and 12) positioned in front of and at the rear of a noise-cancelling transducer diaphragm (8,9) and providing a signal related to the measured noise reduction.</p> |
