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. 25, 2003
Filed:
Jul. 13, 1999
Applicant:
Inventors:
John P. Dilger, Marshalltown, IA (US);
Guojun Liu, Ames, IA (US);
Assignee:
Fisher-Rosemount Systems, Inc., Austin, TX (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04B 1/500 ; G01N 2/902 ;
U.S. Cl.
CPC ...
H04B 1/500 ; G01N 2/902 ;
Abstract
A sensor circuit for use in measuring concentrations of an analyte in a fluid is comprised of a BAW sensor, a voltage variable capacitor connected to the sensor, an input which supplies a bias warping dc voltage to the voltage variable capacitor, and a resonant oscillator circuit. The resonant oscillator circuit detects the fundamental frequency of the sensor and produces a resonant signal frequency. The bias warping dc voltage applied to the voltage variable capacitor warps the resonant frequency of the circuit away from inharmonic noise.