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. 02, 1976
Filed:
Mar. 27, 1974
Kenneth R Hackett, Boulder, CO (US);
Sontrix, Inc., Boulder, CO (US);
Abstract
An ultrasonic or microwave intrusion detection system uses a transmitter having one or more transducers or antennas for maintaining wave fields in the area to be protected and fed by one or more transducers or antennas which detects echo reflections of the energy from within the area. The receiver employs two mixers energized to be mixed with the echo signals and a portion of the energy from the transmitter, one of the mixers receiving such transmitter energy with 90.degree. phase shift relative to the other mixer. The outputs of the two mixers thus are in quadrature phase relative to each other and define a rotating vector which contains the information relating to the echo signals. The product of these quadrature signals obtained by multiplying them together is processed continuously to obtain target information in the presence of substantially larger clutter return signals and other interference. The multiplication of the two quadrature signals to obtain cancellation of the clutter return signals and enhancement of the target signals is achieved without further phase shift requirements by differentiating one of the quadrature signals before it is multiplied with the other quadrature signal. In the preferred embodiment the differentiated quadrature signal is normalized to enhance the dynamic range of the equipment and eliminate the requirement for balanced channels.