CAPACITANCE DETECTION IN ELECTROCHEMICAL ASSAY WITH IMPROVED SAMPLING TIME OFFSET
First Claim
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1. A method of determining capacitance of a biosensor chamber having two electrodes disposed in the chamber and coupled to a microcontroller, the method comprising:
- initiating an electrochemical reaction of a sample upon deposition of the sample in the biosensor chamber;
applying an oscillating signal of a predetermined frequency to the chamber;
ascertaining a first sampling-time interval for measurement of an output signal based on a predetermined sampling rate per cycle of the output signal at the predetermined frequency;
sampling the output signal from the chamber at a second sampling-time interval different than the first sampling-time interval such that a magnitude of each sampled output signal is measured at each succession of the second sampling-time interval instead of at the first time interval;
determining a phase angle between an output signal and the oscillating input signal from the chamber based on the sampled output signal of the sampling step; and
calculating a capacitance of the chamber from the phase angle.
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Abstract
A method and system are provided to determine fill sufficiency of an electrochemical biosensor test cell by determining capacitance of the electrochemical test cell.
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Citations
23 Claims
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1. A method of determining capacitance of a biosensor chamber having two electrodes disposed in the chamber and coupled to a microcontroller, the method comprising:
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initiating an electrochemical reaction of a sample upon deposition of the sample in the biosensor chamber; applying an oscillating signal of a predetermined frequency to the chamber; ascertaining a first sampling-time interval for measurement of an output signal based on a predetermined sampling rate per cycle of the output signal at the predetermined frequency; sampling the output signal from the chamber at a second sampling-time interval different than the first sampling-time interval such that a magnitude of each sampled output signal is measured at each succession of the second sampling-time interval instead of at the first time interval; determining a phase angle between an output signal and the oscillating input signal from the chamber based on the sampled output signal of the sampling step; and calculating a capacitance of the chamber from the phase angle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. An analyte measurement system comprising:
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An analyte test strip including; a substrate having a reagent disposed thereon; at least two electrodes proximate the reagent a in test chamber of the test strip; an analyte meter including; a strip port connector disposed to connect to the two electrodes; a power supply; and a microcontroller electrically coupled to the strip port connector and the power supply, the microcontroller being programmed to; (a) initiate an electrochemical reaction in the biosensor chamber;
apply an oscillating voltage of a predetermined frequency to the chamber;(b) ascertain a first sampling-time interval for measurement of an output signal based on a predetermined sampling rate per cycle of the output signal at the predetermined frequency; (c) sample the output signal from the chamber at a second sampling-time interval different than the first sampling-time interval such that a magnitude of each sampled output signal is measured at each succession of the second sampling-time interval instead of at the first time interval; (d) determine a phase angle between a current output and the oscillating voltage from the chamber based on the sampled output signal; and (e) calculate a capacitance of the chamber based on the determined phase angle. - View Dependent Claims (20, 21, 22, 23)
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Specification