Patent ID: 8774429
Filing Date: 2014-07-08
Classification: H04R

Abstract:
1. A voice input device comprising: a first microphone that includes a first vibrating membrane; a second microphone that includes a second vibrating membrane; and a differential signal generation section that generates a differential signal between a first voltage signal obtained by the first microphone and a second voltage signal obtained by the second microphone based on the first voltage signal and the second voltage signal, wherein the first and second vibrating membranes are disposed so that a noise intensity ratio that represents the ratio of intensity of a noise component contained in the differential signal to intensity of the noise component contained in the first or second voltage signal is smaller than an input voice intensity ratio that represents the ratio of intensity of an input voice component contained in the differential signal to intensity of the input voice component contained in the first voltage signal or the second voltage signal, and wherein the differential signal generation section includes: a delay section that delays at least one of the first voltage signal obtained by the first microphone and the second voltage signal obtained by the second microphone by a predetermined delay amount and outputs the resulting signal; and a differential signal output section that receives the first voltage signal obtained by the first microphone and the second voltage signal obtained by the second microphone, at least one of the first and second voltage signals having been delayed by the delay section, generates a differential signal between the first voltage signal and the second voltage signal, and outputs the differential signal, wherein a center-to-center distance between the first and second vibrating membranes is set at a distance in which a chase component of a voice intensity ratio that is the ratio of the intensity of a differential sound pressure of voices incident on the first and second vibrating membranes to the intensity of a sound pressure of a voice incident on the first vibrating membrane becomes 0 dB or less with respect to sound in a frequency band of 10 kHz or less.