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:
Oct. 11, 1988
Filed:
May. 12, 1986
Erling Frederiksen, Holte, DK;
A/S Bruel & Kjar, Narum, DK;
Abstract
A dual cavity pressure microphone comprising a microphone housing and an oscillating element mounted in or on said housing. The oscillating element including a membrane which is in principle only sensitive to a sound field on one side, the second side forming part of a closed cavity in the microphone housing, said cavity being connected to the ambient atmosphere through a narrow pressure equalizing channel. The microphone comprises an additional cavity representing an additional acoustic capacitance and an additional pressure equalizing channel located in series therewith and representing an additional acoustic resistance, the second capacitance and the second resistane being located in series with the capacitance and resistance, respectively, of the first cavity and the first channel in such a manner, that the pressure equalization of the microphone is also effected through the additional pressure equalizing channel and the additional cavity. According to the invention the additional pressure equalizing channel is dimensioned in such a manner that it substantially only provides a static pressure equalization.