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. 27, 2001
Filed:
Sep. 30, 1999
Nick Anthony Demma, Minneapolis, MN (US);
Honeywell International Inc, Morristown, NJ (US);
Abstract
A system to analyze the impedance of interference-tolerant proximity sensors. A lock-in amplifier (LIA) is implemented as a resonance-tracking oscillator. The control loop of the amplifier monitors the response of sensor in relation to the output of a local oscillator to adjust the oscillator's frequency to resonance. The nature of the sensor acts as a pre-filter of noise for a synchronous demodulator, which demodulates the sensor's response with the local oscillator's driving signal. The output of the system is a filtered version of this demodulated signal. This system is effective in sensing objects in the presence of electromagnetic noise that is many times stronger than the signal produced by the local oscillator.