Set up the FTIR (Fourier Transform Infrared) spectrometer and power it on. Identify an infrared emitting body, one that emits this light at normal atmospheric temperature, such as a red hot stove (see reference 5), and put it in position in front of the spectrometer window. The spectrometer window allows the infrared light beams to enter the system through it. The spectrometer is made up of a fixed mirror, a mirror that moves back and forth and a beam splitter. The light is meant to travel through the beam splitter and the mirrors up to the infrared detector where it is transformed into an electric signal and displayed on a chart for easy interpretation (see reference 4).
Observe the interferogram; the signal diagram displayed on the spectrometer. The interferogram is usually a sinusoidal graph that shows the path of the beam of light and its intensity and also the various wavelengths in the beam. In the interferogram, the x-axis represents the difference between the optical paths which is the wavelength of the light.
Analyze the chart and for each entire wavelength indicate the total number of full waves in one cm of length and by doing this you'll establish its wave number. A full wave is considered as the section of the wavelength between two subsequent crests or troughs. The wave number of a spectrum is related to the energy level of the emission.
Use the Fast Fourier Transform algorithm process to translate the collected interferogram into a spectrum. This process is performed by the internal computer for the FTIR spectrometer and the data is displayed on its screen. Note the wavelength amongst the data and the energy possessed by the beam in volts or watts and calculate its frequency by dividing the velocity of the wave by the wavelength: for example, 3 micrometers in wave length and 527 watts of energy possessed. The velocity of the wave is a constant and is similar to that of visible light.