Asymmetric case for a disk-like BLR such as 3C 120 (i = 10°, R_min = 22 light days, R_max = 28 light days, v_max = 2850 km s^-1). The dotted lines show the time-delay function of the entire BLR (black), the BLR part outside of the filter (red), and the BLR part inside the filter (blue). The centroids of the respective curves are plotted by the vertical solid lines, which virtually coincide.