Empirical distribution of the maximum S/N_AIPS, FFT of the fringe amplitude in the FFT stage of the AIPS fringe-fitting task FRING in the C band (top) and K band (bottom) when no signal was present in the chosen search region (blue points). The search window is constrained to be ±100 ns in delay and ±25 mHz (C band) or ±50 mHz (K band) in rate. The red curve shows the fitted theoretical probability distribution. Note: in addition to a very large difference in the search space size between Figs. A.1 and A.2, S/N_PIMA and S/N_AIPS, FFT are also defined differently.