TIME-DOMAIN (INTERFEROGRAM) AND FREQUENCY-DOMAIN (ABSORPTION-MODE AND MAGNITUDE-MODE) NOISE AND PRECISION IN FOURIER-TRANSFORM SPECTROMETRY

In this paper, we show that precision in determination of time-domain signal parameters by least-squares fit to the time-domain signal itself is similarly related to time-domain initial amplitude-to-noise ratio and the square root of the number of data points per damping period. In addition, we show that although magnitude-mode spectral noise is well described by a Rayleigh distribution in the signal-free baseline segments of the spectrum, noise in the vicinity of a magnitude-mode spectral peak is more accurately described by a normal (Gaussian) distribution. We then proceed to show that determination of spectral parameters from a time-domain data set is more precise by a factor of √2 than estimates based on the FT absorption-mode spectrum.