| 摘要 |
An automatic gain control for a cabin communication system improves the clarity of a voice spoken within a movable interior cabin having ambient noise, the ambient noise intermittently including an undesirable transient noise. The automatic gain control includes a microphone for receiving the spoken voice and the ambient noise and for converting the spoken voice and ambient noise into a first audio signal, the first audio signal including a first component corresponding to the spoken voice and a second component corresponding to the ambient noise, a parameter estimation processor for receiving the first audio signal and for determining parameters for deciding whether or not the second component corresponds to an undesirable transient noise, decision logic for deciding, based on the parameters, whether or not the second component corresponds to an undesirable transient signal, a filter for filtering the first audio signal to provide a filtered audio signal, a loudspeaker for outputting a reproduced voice in response to the filtered audio signal with a variable gain at a second location in the cabin, and a control signal generating circuit for generating an automatic gain control signal in response to the decision logic, wherein when the decision logic decides that the second component corresponds to an undesirable transient signal, the control signal generating circuit generates the automatic gain control signal so as to gracefully set the gain of the loudspeaker to zero for fade-out. |
