| 摘要 |
Disclosed is a method and apparatus for attenuating unwanted frequencies in an acoustical waveguide (26) of a mobile telephone microphone system. One or more Helmholtz resonators (32) is connected to the acoustical waveguide. The Helmholtz resonator's geometry is set to resonate at a frequency to be attenuated. Because the resonator takes that particular tuned frequency and absorbs energy therefrom (in order for the resonator to resonate), the energy level of that frequency is reduced, especially with respect to the acoustic energy of the spectrum transmitted along the waveguide towards the mobile telephone microphone. |
