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:
Apr. 24, 2001
Filed:
May. 10, 1999
John P. Dilger, Marshalltown, IA (US);
Fisher Controls International, Inc., Austin, TX (US);
Abstract
The concentration of an analyte in a fluid is measured by a quartz crystal microbalance sensor device in the fluid containing a concentration of the analyte. The sensor device exhibits a resonant frequency representative of the concentration of the analyte in the fluid. A quartz crystal microbalance reference device has a resonant frequency lower, by a predetermined amount, than the initial resonant frequency of the sensor device before the sensor device is exposed to the analyte. A signal is derived based on the difference of the resonant frequencies of the sensor and the reference device, and a first counter counts a predetermined number of cycles of the difference signal frequency to derive a sample time period. A second counter counts cycles of a clock signal frequency during the sample time period to derive a count representative of the difference signal frequency.