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:
May. 19, 2009
Filed:
Jul. 24, 2006
Welles Reymond, Waterbury, CT (US);
Welles Reymond, Waterbury, CT (US);
Other;
Abstract
An active acoustic intrusion detection system includes a pair of dipole emitters (180 degrees out of phase with each other) which emit an audible frequency f (preferably 1 KHz) and a pair of detectors preferably mounted ¼ wavelength (3 inches) apart in the (non-echoic) nulls of the emitters. The detectors (microphones) spatially sample a stationary wave which is generated by the emitters (speakers). The output of each microphone is fed to an ADC and the digital output of the two ADCs is used to generate a four dimensional vector. At startup, a reference vector is determined and stored. During operation, vectors are sampled, filtered, smoothed and averaged periodically. When an average vector deviates from the reference vector by a set amount, an alarm is generated.