摘要 |
<p>In a speakerphone system (46; and 70), the signal that is directed to a loudspeaker (58) is filtered by a dynamically controllable highpass filter (50). The filter characteristics are adjusted on the basis of the power of the signal and the degree of recent microphone activity (62). The filtered signal is a far-talker signal, while the microphone activity is represented as a near-talker signal that includes an echo component as a consequence of loudspeaker-to-microphone coupling. The degree of microphone activity is determined by a subband analyzer (78). A noise floor estimator (82) may be used to determine the degree to which the near-talker signal is comprised of background noise, so that the noise can be eliminated in the process of controlling the highpass filter.</p> |