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:
Jan. 28, 2003
Filed:
Feb. 12, 1999
John James, Los Gatos, CA (US);
Elf Engineering, Ltd., Houston, TX (US);
Abstract
A low power, frequency-mode magnetometer. The magnetometer includes an LC oscillator, a bias resistor and a polarity switch. The LC oscillator produces an output signal having a variable frequency indicative of both a magnitude and a polarity of a magnetic field. The LC oscillator includes an inverting amplifier and a Pi network including an inductor and two capacitors. The inductor is realized as a coil wound about a high permeability, low hysteresis, core material that has been longitudinally cut. The inductor is coupled between an input node and an output node, as is the inverting amplifier. The inverting amplifier has a first trigger voltage and a second trigger voltage, which are symmetrically located with respect to one half of a DC bias voltage. The bias resistor is coupled between the input node of the LC oscillator and a first node and controls the DC bias current to the inductor. The polarity switch switches the first node between ground and the bias DC voltage.