Netel | Emission Analyzers Filter Correlation is the best type of non-dispersive infra-red for combustion analysis. Instead of a dual beam sample cell and a separate reference cell, this method uses only a single cell for both sample and reference.This method reduces problems with cell contamination, causing a difference in readings. Also, with Gas Filter Correlation, we fill the filter wheel with our own proprietary gas mixtures to eliminate interference from other gases, e.g. H2O or CO2 when measuring. For example, the ppm level of CO is easily measurable in the presence of percent levels of these other gases.Up to five gases can be measured using a single analyzer.  We offer various configurations and options to suit many applications, including internal gas switching for automatic calibration, any combination of separate or combined sample inlets for all of the measurement channels, sample pumps, etc.Our unique design means that we can cater to many combinations of gases. Gases such as CO, CO2, NO, SO2, CH4, HCl, and O2 can be included in many combinations of ranges. For example, a 100 ppm CO range can be used alongside 20% CO2, 1000 ppm NO, 100 ppm SO2 and 25% O2.The PULSAR class also provides superior levels of linearity throughout the 10,0001 range ratio.