Two segments of the RXTE/PCA light curves of MXB 1730−335 in the ρ variability class in the energy bands 2.1–3.8 keV (top panel, black) and 11.4–15.2 keV (central panel, red). A running average smoothing over five bins was applied to reduce the fluctuations and to show clearly the burst structure. The dashed violet horizontal lines correspond to the mean level of the background and the error bar is the statistical error. The superposition of the two data sets, scaled to the same mean amplitude and with the same colours, is plotted in the bottom panel to show that the pulse width does not change with energy.