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:
Mar. 26, 1996
Filed:
Nov. 29, 1993
Sen M Kuo, Houston, TX (US);
Minjiang Ji, DeKalb, IL (US);
M Kathryn Christensen, Lenexa, KS (US);
Robert A Herold, Peoria Heights, IL (US);
Caterpillar Inc., Peoria, IL (US);
Abstract
The system employing and the processing of, an indirectly sensed signal representative of a periodic noise acoustic wave into an input signal for a noise cancelling system where the indirectly sensed signal is converted into a pulse signal per period that carries fundamental and harmonic frequency information of the periodic noise. A tachometer type RPM signal is processed in a counter circuit controlled by a logic circuit to produce a signal of one pulse per revolution with a controlled duration, the pulse amplitude is adjusted, the pulses are low pass filtered and any D.C. is blocked from the noise cancelling system input.