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. 03, 1984
Filed:
Mar. 17, 1982
James F McEachern, State College, PA (US);
The United States of America as represented by the Secretary of the Navy, Washington, DC (US);
Abstract
An improved system is disclosed for calibrating acoustic pressure-sensitive transducers, particularly hydrophones, down to frequencies in the sub-Hertz range. A transducer under test and a reference transducer, both electrically connected to a voltage measuring device, are mounted in aligned proximity to each other upon a pivotal rocker arm immersed in a water tank. A cam and follower unit driven by a motor oscillates the rocker arm so that the transducers are moved through a vertical displacement equivalent to the desired fluctuation of hydrostatic pressure. As a result, calibrations down to 0.01 Hz are achieved.