MIRROR VELOCITY SAMPLING ERRORS IN A MICHELSON INTERFEROMETER

Mirror velocity variations in a continuous mirror drive Michelson inte rferometer result in erroneous interferogram sampling. The effects of both systematic and random mirror fluctuations are evaluated. Four met hods of evaluation provide a means to quantify the importance of mirro r velocity errors in the Fourier spectrometer's performance as a spect roradiometer. The four methods are time interval signal analysis, sine wave test, optical chopper modulation, and examination of consecutive interferograms. Examination of consecutive interferograms includes th e monitoring of a constant blackbody infrared radiation source as well as an interposed ammonia sample cell for wavenumber axis registration . Each method furnishes a known input to the interferometer modulation equation (i.e. 2upsilonnuBAR=f) and permits an internal validation of the interferometer mirror velocity evaluation results.