| 摘要 |
PURPOSE:To suppress an interference tone and to receive only a sound near an object to be desired to receive by causing >=3 microphones, at least, to face to a sound source, arranging them so that a distance between the respective microphones and the sound source can be different, respectively weighting outputs from these microphones, after that, adding the outputs and taking out them. CONSTITUTION:Since a distance L between a main sound source 2 and a microphone device 1 is enough large generally in comparison with sizes DY and DZ of the microphone device 1, a signal from the main sound source 2 can be regarded as a plain wave. A distance l between a noise source 3 and the microphone device 1 is not enough large in comparison with the sizes DY and DZ of the microphone device 1, a signal from the noise source 3 can be regarded as a spherical wave. Accordingly, for the signal from the noise source 3, phase difference is generated by difference l between a distance l to a microphone element to be arranged at a coordinate (YO, ZO) and a distance l' to the microphone element to be arranged at a coordinate (Yi, Zj). Thus, by wholly adding the signals from an nY X nZ-number of microphone elements of the microphone device 1, the signal of the noise source 3 can be suppressed. |
