Frequency evolution of the scattering and mean flux density, and their modelling. Top: pulse profiles of J1227−6208 at f = 902 MHz and f = 1397 MHz as is seen by the MeerKAT L-band receiver (left and middle plots), and at f = 2388 MHz as is seen by the Parkes UWL receiver (right plot). The data (cyan lines) is shown against the best model (red dashes, fitted with equation 1) and the fit residuals (blue lines). The fit parameters τ_s and Δb from equation (1), and the mean flux density F_m are quoted on each profile. Bottom: measurements of Δτ and F_m at each frequency on the MeerKAT L-band and Parkes UWL profiles (dots with uncertainties), and the best fits of the power laws (2) and (3) (red lines). The data points are displayed accounting for the error factors σ_τ and σ_F, and the relevant τ_GHz, α, F_GHz, and β values are quoted in the legend.