Gas concentration measurement by 2F signal trough distance

1. A computer-implemented method executed on a processor for measuring gas concentration from a 2f signal in wavelength modulation spectroscopy, the method comprising:

emitting a beam of light from a laser to pass through a gas sample;

calculating a gas measurement value from the gas sample via a trough distance calculator using a trough distance of a gas absorption line's 2f signal;

calibrating the gas measurement value via a multi-point calibration process; and

outputting the gas measurement value to a user interface of a computing device;

wherein the gas concentration is a linear function of trough distance, the gas concentration given by C=p 1 +p 2 ·D, where C is gas concentration, D is trough distance, and p 1 , p 2 are coefficients.

2. The method of claim 1 , wherein the gas measurement value determined from calculating the trough distance is provided to a training database to be used as training data.

3. The method of claim 1 , wherein the 2f signal trough distance is further employed to determine optical absorption strength of the 2f signal.

4. A computer-implemented method executed on a processor for measuring gas concentration from a 2f signal in wavelength modulation spectroscopy, the method comprising:

emitting a beam of light from a laser to pass through a gas sample;

calculating a gas measurement value from the gas sample via a trough distance calculator using a trough distance of a gas absorption line's 2f signal;

calibrating the gas measurement value via a multi-point calibration process; and

outputting the gas measurement value to a user interface of a computing device;

wherein the gas measurement value is calculated by employing a peak trough height in combination with the trough distance, the peak trough height calculated from a peak trough height calculator; and

wherein the gas concentration is a linear function of the peak trough height and a linear function of the trough distance, the concentration given by C (1) =p 1 +p 2 ·H and by C (2) =p 3 +p 4 ·D, where C is gas concentration, D is trough distance, H is peak trough height, and p 1 -p 4 are coefficients.

5. A computer-implemented method executed on a processor for measuring gas concentration from a 2f signal in wavelength modulation spectroscopy, the method comprising:

emitting a beam of light from a laser to pass through a gas sample;

calculating a gas measurement value from the gas sample via a trough distance calculator using a trough distance of a gas absorption line's 2f signal;

calibrating the gas measurement value via a multi-point calibration process; and

outputting the gas measurement value to a user interface of a computing device;

wherein the gas measurement value is calculated by employing a peak trough height in combination with the trough distance, the peak trough height calculated from a peak trough height calculator; and

wherein the gas concentration is a linear function of the peak trough height, a 3 rd degree polynomial function of the peak trough height, and a linear function of the trough distance, the concentration given by C (1) =p 1 +p 2 ·H, C (2) =p 3 +p 4 H+p 5 H 2 +p 6 H 3 , and C (3) =p 7 +p 8 ·D, where C is gas concentration, D is trough distance, H is peak trough height, and p 1 -p 8 are coefficients.

6. A computer-implemented method executed on a processor for measuring gas concentration from a 2f signal in wavelength modulation spectroscopy, the method comprising:

emitting a beam of light from a laser to pass through a gas sample;

calculating a gas measurement value from the gas sample via a trough distance calculator using a trough distance of a gas absorption line's 2f signal;

calibrating the gas measurement value via a multi-point calibration process; and

outputting the gas measurement value to a user interface of a computing device;

wherein the gas measurement value is calculated by employing a peak trough height in combination with the trough distance, the peak trough height calculated from a peak trough height calculator; and

wherein the gas concentration is a linear function of the peak trough height, an average of two intervals, a 3 rd degree polynomial function of the peak trough height, an average of two other intervals, and a linear function of the trough distance, the concentration given by C (1) =p 1 +p 2 ·H, C (2) =½C (1) +½C (3) , C (3) =p 3 +p 4 H+p 5 H 2 +p 6 H 3 , C (4) =½C (3) +½C (5) , and C (5) =p 7 +p 8 ·D, where C is gas concentration, D is trough distance, H is peak trough height, and p 1 -p 8 are coefficients.

7. A non-transitory computer-readable storage medium comprising a computer-readable program for measuring gas concentration from a 2f signal in wavelength modulation spectroscopy, wherein the computer-readable program when executed on a computer causes the computer to perform the steps of:

emitting a beam of light from a laser to pass through a gas sample;

calculating a gas measurement value from the gas sample via a trough distance calculator using a trough distance of a gas absorption line's 2f signal;

calibrating the gas measurement value via a multi-point calibration process; and

outputting the gas measurement value to a user interface of a computing device;

wherein the gas concentration is a linear function of trough distance, the gas concentration given by C=p 1 +p 2 ·D, where C is gas concentration, D is trough distance, and p 1 , p 2 are coefficients.

8. The non-transitory computer-readable storage medium of claim 7 , wherein the gas measurement value determined from calculating the trough distance is provided to a training database to be used as training data.

9. The non-transitory computer-readable storage medium of claim 7 , wherein the 2f signal trough distance is further employed to determine optical absorption strength of the 2f signal.

10. A non-transitory computer-readable storage medium comprising a computer-readable program for measuring gas concentration from a 2f signal in wavelength modulation spectroscopy, wherein the computer-readable program when executed on a computer causes the computer to perform the steps of:

emitting a beam of light from a laser to pass through a gas sample;

calculating a gas measurement value from the gas sample via a trough distance calculator using a trough distance of a gas absorption line's 2f signal;

calibrating the gas measurement value via a multi-point calibration process; and

outputting the gas measurement value to a user interface of a computing device;

wherein the gas measurement value is calculated by employing a peak trough height in combination with the trough distance, the peak trough height calculated from a peak trough height calculator; and

wherein the gas concentration is a linear function of the peak trough height and a linear function of the trough distance, the concentration given by C (1) =p 1 +p 2 ·H and by C (2) =p 3 +p 4 ·D, where C is gas concentration, D is trough distance, H is peak trough height, and p 1 -p 4 are coefficients.

11. A non-transitory computer-readable storage medium comprising a computer-readable program for measuring gas concentration from a 2f signal in wavelength modulation spectroscopy, wherein the computer-readable program when executed on a computer causes the computer to perform the steps of:

emitting a beam of light from a laser to pass through a gas sample;

calculating a gas measurement value from the gas sample via a trough distance calculator using a trough distance of a gas absorption line's 2f signal;

calibrating the gas measurement value via a multi-point calibration process; and

outputting the gas measurement value to a user interface of a computing device;

wherein the gas measurement value is calculated by employing a peak trough height in combination with the trough distance, the peak trough height calculated from a peak trough height calculator; and

wherein the gas concentration is a linear function of the peak trough height, a 3 rd degree polynomial function of the peak trough height, and a linear function of the trough distance, the concentration given by C (1) =p 1 +p 2 ·H, C (2) =p 3 +p 4 H+p 5 H 2 +p 6 H 3 , and C (3) =p 7 +p 8 ·D, where C is gas concentration, D is trough distance, H is peak trough height, and p 1 -p 8 are coefficients.

12. A non-transitory computer-readable storage medium comprising a computer-readable program for measuring gas concentration from a 2f signal in wavelength modulation spectroscopy, wherein the computer-readable program when executed on a computer causes the computer to perform the steps of:

emitting a beam of light from a laser to pass through a gas sample;

calculating a gas measurement value from the gas sample via a trough distance calculator using a trough distance of a gas absorption line's 2f signal;

calibrating the gas measurement value via a multi-point calibration process; and

outputting the gas measurement value to a user interface of a computing device;

wherein the gas measurement value is calculated by employing a peak trough height in combination with the trough distance, the peak trough height calculated from a peak trough height calculator; and

wherein the gas concentration is a linear function of the peak trough height, an average of two intervals, a 3 rd degree polynomial function of the peak trough height, an average of two other intervals, and a linear function of the trough distance, the concentration given by C (1) =p 1 +p 2 ·H, C (2) =½C (1) +½C (3) , C (3) =p 3 +p 4 H+p 5 H 2 +p 6 H 3 , C (4) =½C (3) +½C (5) , and C (5) =p 7 +p 8 ·D, where C is gas concentration, D is trough distance, H is peak trough height, and p 1 -p 8 are coefficients.

13. A system for measuring gas concentration from a 2f signal in wavelength modulation spectroscopy, the system comprising:

a laser to emit a beam of light to pass through a gas sample;

a gas measurement value calculated from the gas sample via a trough distance calculator using a trough distance of a gas absorption line's 2f signal;

a multi-point calibration system to calibrate the gas measurement value; and

a user interface of a computing device to output the gas measurement value;

wherein the gas concentration is a linear function of trough distance, the gas concentration given by C=p 1 +p 2 ·D, where C is gas concentration, D is trough distance, and p 1 , p 2 are coefficients.

14. A system for measuring gas concentration from a 2f signal in wavelength modulation spectroscopy, the system comprising:

a laser to emit a beam of light to pass through a gas sample;

a gas measurement value calculated from the gas sample via a trough distance calculator using a trough distance of a gas absorption line's 2f signal;

a multi-point calibration system to calibrate the gas measurement value; and

a user interface of a computing device to output the gas measurement value;

wherein the gas measurement value is calculated by employing a peak trough height in combination with the trough distance, the peak trough height calculated from a peak trough height calculator; and

wherein the gas concentration is a linear function of the peak trough height and a linear function of the trough distance, the concentration given by C (1) =p 1 +p 2 ·H and by C (2) =p 3 +p 4 ·D, where C is gas concentration, D is trough distance, H is peak trough height, and p 1 -p 4 are coefficients.