Separation of real DPSs (2001 April 11 radio dynamic spectrum): a) original radio spectrum with DPSs; b) averaged global spectrum (ASf) with a peak for the frequency width = 450 MHz; c) radio spectrum filtered from ASf in the frequency width range = 290−540 MHz; d) averaged global spectrum (ASt) made from the spectrum in the panel c) with peaks for the periods P = 4.7, 8.5, 16.0, and 29.0 s; e) separated DPSs in the period range 2.2−5.5 s; f) separated DPSs in the period range 5.5−10.0 s; g) separated DPSs in the period range 10−20 s; and h) separated DPSs in the period range 20−44 s. Arrows in panels show frequency drifts of DPSs (see Sect. 3.2). The positive and negative parts of amplitudes (in relation to their mean values) are given in white and black, respectively (panels c) and e − h)).