| 摘要 |
PROBLEM TO BE SOLVED: To provide an automatic microphone sensitivity controller that controls microphone sensitivity to be almost constant regardless of a distance between the position of a voice generating source and the position of a microphone. SOLUTION: A level detector 6 samples an output voice signal outputted from a microphone 1 in each prescribed time interval for a predetermined period, and the gain of a microphone amplifier 2 is changed just by a predetermined value under the control of a control circuit 8 when an output voice signal level sampled for the predetermined period comes to within the range of a threshold stored in a memory 7 over the predetermined number of times or more, thereby substantially controlling microphone sensitivity at a constant level. COPYRIGHT: (C)2005,JPO&NCIPI |
