| 摘要 |
An active headset providing for reduction of external noise over a given frequency range by means of a microphone which generates an external noise representative signal processed and fed to a loudspeaker to produce an external noise cancellation signal spectrum, wherein a bridge amplifier circuit is interposed between the microphone and the loudspeaker and the gain of the bridge amplifier for peak amplitude of the noise cancellation signal is user adjustable without substantially reducing the breadth of the given frequency range over which noise reduction is effective. |
