Patent ID: 7524460
Filing Date: 2009-04-28
Classification: G01N,Y10T

Abstract:
1. A chemical sensor system comprising: a surface acoustic wave (SAW) sensor comprising a primary surface having a total area and an active zone within the total area, and wherein the SAW sensor is configured to produce an oscillatory output signal responsive to adsorption of molecules of a chemical analyte by the active zone on the primary surface; a frequency fluctuation counter configured to measure a plurality of frequency fluctuations of said oscillatory output signal; amplitude density means, coupled to said frequency fluctuation counter, for generating an amplitude density signal representative of the amplitude density of said plurality of frequency fluctuations; and a pattern recognizer configured to receive the amplitude density signal, wherein the pattern recognizer is also configured to generate an analyte output signal representative of a total number n of said adsorbed molecules if said amplitude density signal corresponds to a theoretical amplitude density function P(r,n) which is substantially represented by the equation: wherein n and r are nonnegative integers, r≦n, n represents a theoretical total number of molecules on a surface of a virtual SAW sensor, r represents a theoretical number of molecules on an active zone of said virtual SAW sensor, and wherein p is substantially represented by: p=μ active /μ total , where μ total is the total surface area of said surface and μ active is the area of said active zone, wherein said active zone is used to measure an output signal and wherein said total area of said surface is the total area of said SAW device over which an acoustic wave is generated.