ANALYZER SYSTEM AND OPTICAL FILTERING

1 . A system comprising:

an optical source to generate an optical signal;

an optical filter assembly including different optical filters in which to filter the optical signal;

a controller configured to select sequential application of each of the different optical filters in a path of the optical signal to modulate the optical signal; and

an optical analyzer to analyze the modulated optical signal passing through a sample to detect which of multiple gases are present in the sample.

2 . The system as in claim 1 , wherein the optical analyzer is configured to determine a concentration of multiple gases present in the sample based on how much of the modulated optical signal is absorbed by the sample at different optical energies, at least two of the multiple gases present in the sample absorbing optical energy in a common frequency band of the modulated optical signal.

3 . The system as in claim 2 , wherein the optical filter assembly includes an optical filter to pass optical energy of the optical signal in the common frequency band through the sample to the optical analyzer.

4 . The system as in claim 1 , wherein the optical assembly is an optical filter wheel including the different optical filters, the different optical filters of the optical filter wheel separated by opaque partitions that block the optical signal from passing through the sample.

5 . The system as in claim 4 , wherein the controller is configured to rotate the optical wheel to each of multiple successive positions including a first position, a second position, and a third position;

the first position of the optical filter wheel aligning a first filter of the optical filter wheel with a path of the optical signal enabling the optical signal to pass through the first optical filter and the sample to the analyzer;

the second position of the optical filter wheel placing an opaque partition of the optical wheel in a path of the optical signal such that the optical signal does not pass through the sample to the analyzer; and

the third position of the optical filter wheel aligning a second filter of the optical filter wheel with the path of the optical signal enabling the optical signal to pass through the second optical filter and the sample to the analyzer.

6 . The system as in claim 1 , wherein the multiple filters include a first optical filter and a second optical filter;

the first optical filter configured to pass a first optical frequency energy band of the optical signal through the sample to the analyzer; and

the second optical filter configured to pass a second optical frequency energy band of the optical signal through the sample to the analyzer, the first optical frequency band being different than the second optical frequency band.

7 . The system as in claim 6 , wherein the controller is configured to generate the modulated optical signal based on positioning the first optical filter in a path of the optical signal generated by the optical source and thereafter positioning the second optical filter in the path of the optical signal generated by the optical source.

8 . The system as in claim 1 , wherein the sample is a flue sample at least partially derived based on burning of fossil fuels; and

wherein the optical analyzer is configured to analyze the modulated optical signal passing through the flue sample to detect which of the multiple gases are present in the flue sample.

9 . The system as in claim 1 , wherein the optical source generates the optical signal in an infrared frequency range.

10 . The system as in claim 1 , wherein at least one of the multiple optical filters is a reference filter in which none of the multiple gases in the sample absorb optical energy.

11 . The system as in claim 1 , wherein the optical analyzer is configured to detect a relative peak optical energy of the modulated optical signal that passes through the sample for each of the filters in the optical filter assembly.

12 . A method comprising:

generating an optical signal to pass through a sample;

selecting application of each of different optical filters in a path of the optical signal to modulate the optical signal; and

analyzing the modulated optical signal after passing of the modulated optical signal through the sample to detect which of multiple gases are present in the sample.

13 . The method as in claim 12 further comprising:

determining a concentration of multiple gases present in the sample based on how much of the modulated optical signal is absorbed by the sample at different optical energies.

14 . The method as in claim 12 further comprising:

producing the modulated optical signal based on positioning of different optical filters and opaque partitions in the path of the optical signal, each of the different optical filters passing different optical frequency bands of the optical signal through the sample.

15 . The method as in claim 12 further comprising:

producing the modulated signal by rotating an optical filter wheel to each of multiple successive positions including a first position, a second position, and a third position:

the first position of the optical filter wheel aligning a first filter of the optical filter wheel in the path of the optical signal to enable the optical signal to pass through the first optical filter and the sample to an analyzer that analyzes the optical signal;

the second position of the optical filter wheel aligning an opaque partition of the optical wheel in a path of the optical signal such that the optical signal does not pass through the sample; and

the third position of the optical filter wheel aligning a second filter of the optical filter wheel in the path of the optical signal enabling the optical signal to pass through the second optical filter and the sample to the analyzer.

16 . The method as in claim 12 , wherein selecting application of each of the different optical filters in the path of the optical signal to modulate the optical signal includes:

disposing a first optical filter in the path of the optical signal for a first duration of time, the first optical filter configured to pass a first optical frequency energy band of the optical signal through the sample; and

subsequent to the first duration of time, disposing a second optical filter in the path of the optical signal for a second duration of time, the second optical filter configured to pass a second optical frequency energy band of the optical signal through the sample.

17 . The method as in claim 12 , wherein generating the optical signal includes generating the optical signal in an infrared frequency range.

18 . The method as in claim 12 , wherein analyzing the modulated optical signal after passing of the modulated optical signal through the sample includes, for each of multiple filters, detecting an amount of optical energy in the modulated optical signal after passing of the optical energy through the sample for each of the multiple filters.

19 . A computer readable medium having computer code thereon, the medium comprising:

instructions for generating an optical signal to pass through a sample;

instructions for selecting application of each of different optical filters in a path of the optical signal to modulate the optical signal; and

instructions for analyzing the modulated optical signal after passing of the modulated optical signal through the sample to detect which of multiple gases are present in the sample.

20 . The computer readable medium as in claim 19 further comprising:

instructions for producing the modulated optical signal based on positioning of different optical filters and opaque partitions in the path of the optical signal, each of the different optical filters passing different optical frequency bands of the optical signal through the sample.