prepfold diagnostic plot. The candidate stands out when it displays a pulsar-like integrated profile (top subpanels; two rotations shown) and a near-constant period when it is demodulated at the orbit of the trial companion (bottom subpanels). Left (a): Candidate with a period of 2.059 s. Middle (b): Candidate with a period of 4.019 s. Right (c): Candidate with a period of 42 ms.