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:
Aug. 08, 2000
Filed:
Sep. 15, 1999
Klaus V Pieverling, Wolfratshausen, DE;
Siemens Aktiengesellschaft, Munich, DE;
Abstract
A vehicle detectors with at least one inductive loop is used as a sensor. An oscillator circuit comprises a fixed-frequency oscillator, which is directly connected to one of the inductive loops' two terminals, for purposes of exciting said loop. In addition, a phase/amplitude controller is arranged between the fixed-frequency oscillator and the other terminal, which forms a summation point of the inductive loop to deliver a compensation signal that is derived from the transmit signal in an amplitude-controlled and phase-controlled manner. The inductive loop, the fixed-frequency oscillator and the phase/amplitude controller form a bridge circuit in which (with reference to the resulting voltage at the summation point) the transmit signal and the compensation signal add up to zero in the resting state of the inductive loop. A detection signal for the presence of a vehicle in the detection range of the induction loop is derived from a voltage at this summation point which deviates therefrom.