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:
Feb. 01, 1994
Filed:
Aug. 26, 1991
Applicant:
Inventors:
Seth D Goodman, Madison, WI (US);
Kirk G Burlage, Madison, WI (US);
Assignee:
Nelson Industries, Inc., Stoughton, WI (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H03B / ;
U.S. Cl.
CPC ...
381 71 ; 381 72 ; 381 94 ;
Abstract
Detection of higher order mode transverse modal energy is suppressed for an acoustic wave propagating longitudinally through a duct. First and second microphones are placed in respective first and second nodal planes of the second higher order mode, and the outputs of the microphones are summed. For the first higher order mode, the output of the first microphone is equal in amplitude and opposite in phase to the output of the second microphone, and the resultant sum is zero. For the second higher order mode, the output of each of the first and second microphones is zero, and the resultant sum is zero.