Hand-held test mester with low-distortion signal generation circuit

• US 9,470,649 B2
• Filed: 06/10/2014
• Issued: 10/18/2016
• Est. Priority Date: 06/10/2014
• Status: Active Grant

• Current Assignee: Cilag Gmbh International (Johnson & Johnson)
• Original Assignee: LifeScan Scotland Limited (Johnson & Johnson)
• Inventors: Elder, David, Massari, Rossano
• Primary Examiner(s): NGUYEN, HOAI AN D
• Application Number:
  US14/300,454
• Publication Number:
  US 20150355131A1
• Time in Patent Office: 861 Days
• Field of Search: 324/620, 324/612, 324/600, 205/775, 205/792, 435/4, 435/14
• US Class Current: 1/1
• CPC Class Codes: G01N 27/3271 Amperometric enzyme electrodes for analytes in body fluids, e.g. glucose in blood amperometry per se G01N27/49; aspects concerning the enzyme reagent C12Q1/001
• CPC Class Codes: G01N 27/3273 Devices therefor, e.g. test element readers, circuitry details not specific to biochemical electrodes G01N33/4875
• CPC Class Codes: G01N 27/3274 Corrective measures, e.g. error detection, compensation for temperature or hematocrit, calibration coding of calibration information G01N33/48771
• CPC Class Codes: G01R 23/20 Measurement of non-linear distortion
• CPC Class Codes: G01R 29/26 Measuring noise figure; Measuring signal-to-noise ratio

Abstract

A hand-held test meter for use with an analytical test strip in the determination of an analyte in a bodily fluid sample includes a housing, a clock module disposed in the housing, a micro-controller disposed in the housing, a low-distortion signal generation circuit block (“LDSGCB”) disposed in the housing, and a strip port connector configured to operationally receive the analytical test strip. The LDSGCB includes a signal summation circuit (“SSC”) sub-block, a resistance-capacitance (RC) filter, and a single operational amplifier. The clock module and micro-controller are configured to generate phase-shifted square wave signals and output the phase-shifted square wave signals to the SSC. The SSC is configured to sum the phase-shifted square wave signals to generate a resultant summed-wave signal and output the resultant summed-wave signal to the RC filter. The RC filter is configured to filter harmonics from the resultant summed-wave signal thereby creating a reduced harmonic distortion signal.

Claims

1. A hand-held test meter for use with an analytical test strip in the determination of an analyte in a bodily fluid sample, the hand-held test meter comprising:

a housing;

a clock module disposed in the housing;

a micro-controller disposed in the housing;

a low-distortion signal generation circuit disposed in the housing that includes;

a signal summation circuit;

a resistance-capacitance (RC) filter; and

a single operational amplifier; and

a strip port connector configured to operationally receive an analytical test strip; and

wherein the clock module and micro-controller are configured to generate a plurality of phase-shifted square wave signals and output the plurality of phase-shifted square wave signals to the signal summation circuit; and

wherein the signal summation circuit is configured to sum the plurality of phase-shifted square wave signals to generate a resultant summed-wave signal and output the resultant summed-wave signal to the RC filter; and

wherein the RC filter is configured to filter harmonics from the resultant summed-wave signal thereby creating a reduced harmonic distortion signal; and

wherein the single operational amplifier is configured to amplify the reduced harmonic distortion signal to produce an amplified reduced harmonic distortion signal that is output to an analytical test strip received in the strip port connector.

2. The hand-held test meter of claim 1 further including a signal phase and magnitude measurement circuit.

3. The hand-held test meter of claim 1 wherein the plurality of phase-shifted square wave signals includes a first phase-shifted square wave signal and a second phase-shifted square wave signal.

4. The hand-held test meter of claim 3 wherein the first phase-shifted square wave signal and the second phase shifted square wave signal have a phase difference in the range of 45 degrees to 75 degrees.

5. The hand-held test meter of claim 4 wherein the first phase-shifted square wave signal and the second phase shifted square wave signal have a phase difference of 60 degrees.

6. The hand-held test meter of claim 1 wherein the microcontroller includes:

a timer; and

wherein the timer is employed to create the plurality of phase-shifted square waves.

7. The hand-held test meter of claim 1 wherein the resultant summed wave signal approximates a sine wave signal and is essentially-free of 3^rd order harmonics.

8. The hand-held test meter of claim 1 wherein the amplified reduced harmonic distortion signal has a total harmonic distortion of less than 1.1%.

9. The hand-held test meter of claim 1 wherein the analytical test strip is an electrochemical-based analytical test strip configured for the determination of glucose and hematocrit of a bodily fluid sample.

10. The hand-held test meter of claim 1 wherein the clock module, micro-controller and low-distortion signal generation circuit are configured to measure the phase shift of a bodily fluid sample in a sample cell of an analytical test strip inserted in the hand-held test meter by forcing amplified low distortion signal of through the bodily fluid sample.

11. The hand-held test meter of claim 1 wherein the amplified reduced harmonic distortion signal is an amplified reduced harmonic distortion sine wave signal.

12. A method for employing a hand-held test meter and analytical test strip, the method comprising:

inserting an analytical test strip into a strip port connector of a hand-held test meter;

generating, using a clock module and a micro-controller of the hand-held test meter, a plurality of phase-shifted square wave signals and outputting the plurality of phase-shifted square wave signals to a low-distortion signal generation circuit of the hand-held test meter;

employing a signal summation circuit, resistance-capacitance (RC) filter and single operational amplifier of the low-distortion signal generation to sum the plurality of phase-shifted square wave signals to generate a resultant summed-wave signal and filter harmonics from the resultant summed-wave signal to thereby create a reduced harmonic distortion signal; and

amplify the reduced harmonic distortion signal to produce an amplified reduced harmonic distortion signal that is output to the analytical test strip received in the strip port connector; and

determining at least one of an analyte in, and a characteristic of, a bodily fluid sample applied to the analytical test strip using the amplified reduced harmonic distortion signal.

13. The method of claim 12 wherein the employing includes employing the amplified reduced harmonic distortion signal to determine hematocrit of a whole blood sample applied to the analytical test strip.

14. The method of claim 12 wherein the plurality of phase-shifted square waves are a first phase-shifted square wave and a second phase-shifted square wave, a sine wave.

15. The method of claim 14 wherein the amplified reduced harmonic distortion signal is a sine wave.

16. The method of claim 14 wherein the first phase-shifted square wave signal and the second phase shifted square wave signal have a phase difference in the range of 45 degrees to 60 degrees.

17. The method of claim 16 wherein the wherein the first phase-shifted square wave signal and the second phase shifted square wave signal have a phase difference of 60 degrees.

18. The method of claim 12 wherein the first phase-shifted square wave signal and the second phase shifted square wave signal are digital signals.

19. The method of claim 12 wherein the amplified reduced harmonic distortion signal is a sine wave signal.

20. The method of claim 19 wherein the amplified reduced harmonic distortion signal is a sine wave signal with a total harmonic distortion of less than 1.1%.

21. The method of claim 19 wherein the amplified reduced harmonic distortion signal is a sine wave signal essentially free of 3^rd order harmonics.

22. A hand-held test meter for use with an analytical test strip in the determination of an analyte in a bodily fluid sample, the hand-held test meter comprising:

a housing;

a clock module disposed in the housing;

a micro-controller disposed in the housing;

a low-distortion signal generation circuit disposed in the housing that includes;

a signal summation circuit; and

a single operational amplifier; and

a strip port connector configured to operationally receive an analytical test strip; and

wherein the clock module and micro-controller are configured to generate a plurality of phase-shifted square wave signals and output the plurality of phase-shifted square wave signals to the signal summation circuit; and

wherein the signal summation circuit is configured to sum the plurality of phase-shifted square wave signals to generate a resultant summed-wave signal and output the resultant summed-wave signal to the single operational amplifier; and

wherein the single operational amplifier is configured to amplify the resultant summed wave signal to produce an amplified low-distortion signal that is output to an analytical test strip received in the strip port connector.

23. The hand-held test meter of claim 22 wherein the amplified low-distortion signal is an amplified low-distortion triangular signal.

24. The hand-held test meter of claim 22 wherein the amplified low-distortion signal is an amplified low-distortion trapezoidal signal.

25. A method for employing a hand-held test meter and analytical test strip, the method comprising:

inserting an analytical test strip into a strip port connector of a hand-held test meter;

generating, using a clock module and a micro-controller of the hand-held test meter, a plurality of phase-shifted square wave signals and outputting the plurality of phase-shifted square wave signals to a low-distortion signal generation circuit of the hand-held test meter;

employing a signal summation circuit and single operational amplifier of the low-distortion signal generation to sum the plurality of phase-shifted square wave signals to generate a resultant summed-wave signal and to amplify the resultant summed-wave signal to produce an amplified low-distortion signal that is output to the analytical test strip received in the strip port connector; and

determining at least one of an analyte in, and a characteristic of, a bodily fluid sample applied to the analytical test strip using the amplified low-distortion signal.

26. The method of claim 25 wherein the amplified low-distortion signal is an amplified low-distortion triangular signal.

27. The method of claim 25 wherein the amplified low-distortion signal is an amplified low-distortion trapezoidal signal.