| 摘要 |
PURPOSE: An ear microphone is provided to eliminate a noise signal entering into an external auditory canal by outputting a signal having an opposite phase to that of the noise signal which enters into the external auditory canal through a cover or a housing. CONSTITUTION: A first microphone(135) changes an external noise signal into a first electrical signal having an opposite phase to that of an external noise signal. A signal processor(170) filters the first electrical signal. The signal processor adds the filtered signal and a second electric signal provided from an external device. A speaker(120) outputs an added signal of the first electrical signal and the second electric signal to an external auditory canal by receiving an output signal of the signal processor. The external noise signal which enters into the external auditory canal is offset by the first electrical signal which is outputted through a speaker. [Reference numerals] (AA) External auditory meatus |
