Patent 7961893 was granted and assigned to Sony on June, 2011 by the United States Patent and Trademark Office.
A measuring apparatus that measures sound arrival delay time from a speaker to a microphone on the basis of a result obtained by collecting signals output from the speaker by means of the microphone includes: measuring means for measuring the sound arrival delay time that makes a control such that a first sine wave signal having a first frequency and a second sine wave signal having a second frequency different from the first frequency are output from the speaker, is input with the first sine wave signal and the second sine wave signal collected by the microphone and then mixes the first sine wave signal and the second sine wave signal so as to generate a third sine wave signal having a frequency corresponding to a difference between the first frequency and the second frequency, and measures the sound arrival delay time on the basis of the third sine wave signal.