An experimental setup is developed to analyze infrared emission of CO2 plasmas at atmospheric pressure and temperatures up to 5000 K. A microwave discharge is used to produce the hot gas mixture and emission is recorded by a Fourier transform spectro- meter with a spectral resolution between 0.01 and 0.1cm-1. The plasma is confined inside quartz or sapphire tubes which perturb the measurements through refraction, reflection, absorption and emission. We present in this part the experimental setup, an analysis of tube effects, and the characterization of the plasma in terms of temperature and molar fraction distributions using CO emission in the overtone vibrational bands Dv= 2. Analysis of the measurements of CO2 emission in the 2.7 and 4.3 micrometers regions, and comparisons with calculations using different spectroscopic databases are given in the companion paper (Depraz et al., in press) [1].