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:
Nov. 29, 1994
Filed:
Feb. 26, 1993
Stephen R Cooper, Tustin, MI (US);
David W Shank, Big Rapids, MI (US);
Carl A Munch, Southfield, MI (US);
Nadi S Findikli, Forest, VA (US);
Nartron Corporation, Reed City, MI (US);
Abstract
An integrated circuit for driving a sensor includes an oscillator for providing a first clock signal synchronized to a periodic waveform supplied by an external source. A second clock signal in the form of a uni-polar square wave is derived from the first clock signal. A sinewave signal is generated by consecutively selecting voltage steps from a resistor ladder under control of the second clock signal. A low-pass filter removes from the sinewave signal higher frequency harmonics generated by switching through the steps of the resistor ladder. A linear amplifier utilizes an external capacitor to couple the filtered sinewave signal to the sensor. Temperature compensation is provided by comparing the voltage of the sinewave signal supplied to the sensor with an external temperature stable reference voltage. The integrated circuit also includes circuitry for amplitude demodulating a signal returned from the sensor to provide a sensor output signal.