Gas correlation filter wheel and gas analyzer

A gas correlation filter wheel for a gas analyzer of a gas correlation system, comprising:

• a plurality of gas filters;
• and
• a wheel configured to house the plurality of gas filters along a circumference of a circle concentric with the wheel,
• wherein:
• each of the gas filters includes a housing that is tubular, light transmitting windows sealing both ends of the housing, and an optical filter positioned on one of the light transmitting windows;
• and
• the plurality of gas filters include at least a first gas correlation filter set and a second gas correlation filter set,
• the first gas correlation filter set including:
• a first target gas filter, in which a first target gas is sealed;
• and
• a first reference gas filter sealed with a reference gas that does not absorb an infrared ray,
• the optical filter of the first target gas filter and the optical filter of the first reference gas filter being configured to selectively transmit wavelengths of the infrared ray that are same as those absorbed by the first target gas, and
• the second gas correlation filter set including:
• a second target gas filter in which a second target gas is sealed;
• and
• a second reference gas filter sealed with the reference gas that does not absorb the infrared ray,
• the optical filter of the second target gas filter and the optical filter of the second reference gas filter being configured to selectively transmit wavelengths of the infrared ray that are same as those absorbed by the second target gas.