The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 29, 1986
Filed:
Feb. 02, 1984
Makoto Kohashi, Kanagawa, JP;
Tanetoshi Miura, Kokubunji, JP;
Kaoru Okabe, Kunitachi, JP;
Haruo Hamada, Mitaka, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
An earphone characteristic measuring device comprises an acoustic coupler having an acoustic tube simulated to an external auditory canal in which an earphone under measurement is to be inserted and an acoustic tube of a smaller diameter having an acoustic impedance of approximately 320 ohms connected to an end of the first acoustic tube, a sound source for emitting an impulse sound to the acoustic coupler, a microphone mounted at the end of the first acoustic tube for picking up sound pressure information and a characteristic calculation circuit for transforming an earphone characteristic of the acoustic coupler to an earphone characteristic of a real ear based on an input impedance of the acoustic coupler viewed from an end of the earphone inserted in the acoustic coupler and an input impedance of the real ear represented by a sum of an eardrum impedance of the real ear and an external auditory canal volume of the real ear, stored in a memory in response to the sound pressure information from the microphone. The use of the acoustic coupler of a simple structure facilitates the measurement of a vent characteristic of the earphone and an insertion gain and improves reliability of the measurement.