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:
Jun. 29, 1999
Filed:
Sep. 27, 1996
Roger D Malin, Glendale, AZ (US);
Other;
Abstract
A high sensitive water entry alarm system which prevents outside noise from falsely triggering the alarm system. A transmitter generates ultrasonic timed acoustic bursts at a fixed frequency when it is submerged in water. A receiver located in the body of water senses for acoustic signals similar in characteristic to the transmitter signal. A comparing circuit coupled to the receiver compares the acoustic signals received by the receiver to a reference signal having the same fixed frequency as the transmitter signal. The comparing circuit also measures the duration of the acoustic signals received by the receiver. The comparing circuit will generate a alarm signal which will sound off an audible alarm only when the acoustic signal received by the receiver has the same fixed frequency and is transmitted in controlled burst at the same timed intervals as the transmitter signal.