Multigas digital correlation spectrometer

Claim 1

A spectrometer for monitoring a gaseous mixture in order to detect a component gas of interest in said mixture, comprising in combination: a source of monochromatic radiation disposed to irradiate said mixture; means for periodically sweeping said source through a predetermined spectrum of frequencies; means disposed to receive the radiation emerging from said mixture and produce an electrical analogue signal which is a function of the intensity of the radiation received; means synchronized with said periodically sweeping means for converting said electrical analogue signal to an output signal comprising series of binary numerical electrical signals representative of said analogue electrical signal to a plurality of discrete predetermined wavelengths; means for storing a plurality of binary numbers whose values are a function of a spectrum of a component gas of interest at said discrete, predetermined wavelengths; and means for correlating the binary output signal of said converting means with the binary numbers in said storage means including means to divide the output of said converting means by a series of binary numbers whose values are a function of the values of the output of the converter means at said predetermined wavelengths for a predetermined absorption by a gas mixture and means for subtracting the output of said divider means from one, means for multiplying the output of said subtracter means with the numbers stored in said storage means, and means for summing the output of said multiplier means.