Infrared background data are usually presented in the form of time histories and various statistics. The statistics in the time domain include means, variances, a utocorrelations, and histograms of various types. The statistic usually presented in the frequency domain is power spectral density. The data in either the time or the frequency domain may be useful, depending on how the system designer chooses to implement his filtering system and perform his system calculation. This paper examines the requirement for consistency in the two domains and shows how well certain windowing techniques assure con-sistency between the time and frequency domains. A particular technique is shown to give virtually perfect consistency. Data from the Balloon Altitude Mosaic Measurement (BAMM) are used to illustrate the results.