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:
Oct. 22, 1985
Filed:
Jun. 02, 1983
Uwe Metzner, Munich, DE;
Siemens Aktiengesellschaft, Berlin & Munich, DE;
Abstract
A plurality of transmitters operating at respective frequencies is connected to at least some electrodes of a capacitive security fence. Each electrode is provided with a transformer whose primary winding is connected between the transmitter and ground. The secondary of each transformer is connected to a plurality of bandpass filters having adjustable center frequencies which correspond to the transmitter frequencies. The voltage available at the outputs of the bandpass filters are fed to a measuring device and supplied to a microcomputer. The interelectrode capacitances and the self-capacitances of the electrodes of the system are identified from the measured voltages which are proportional to the capacitances.