Abstract: Apparatus utilizing change in pressure condition in an area to be protected to indicate intrusion or change in conditions of the area by means of a pressure detection device to detect pressure waves at low and infrasonic frequencies which includes a pressure transducer sensitive to change in pressure to provide an output signal. In some instances an amplifier is provided to amplify the output signal, a signal conditioning circuit is provided to delay a portion of the signal, and a detector device is provided to detect the signal with a comparator provided to compare the signal with the delayed signal and actuate an alarm.
Type:
Grant
Filed:
June 20, 1991
Date of Patent:
February 9, 1993
Assignee:
Bluegrass Electronics, Inc.
Inventors:
Elden E. DuRand, III, William K. Logsdon
Abstract: Apparatus utilizing change in pressure condition in an area to be protected to indicate intrusion or change in conditions of the area by using a pressure detection device to detect pressure waves at low and infrasonic frequencies which includes a pressure transducer sensitive to change in pressure to provide an output signal. In some instances an amplifier is provided to amplify the output signal, a signal conditioning circuit is provided to delay a portion of the signal, and a detector device is provided to detect the signal with a comparator provided to compare the signal with the delayed signal and actuate an alarm.
Type:
Grant
Filed:
May 30, 1989
Date of Patent:
May 22, 1990
Assignee:
Bluegrass Electronics, Inc.
Inventors:
Elden E. DuRand, III, William K. Logsdon
Abstract: A device for selecting the proper sensitivity and acceptable background noise level for sound discrimination switches used for detection of selected sounds where the detection device includes peak signal detectors to receive audio voltage generated by the selected sounds and activate an alarm.