Example of the pFDMT algorithm using eight frequency channels. The de-dispersion is only applied to DM = [1, 2], resulting in a de-dispersed sub-band data of two frequency channels. The output data are shaded in blue. The start DM is 0 and the DM step is 1, both of which can be adjusted. The solid red line indicates that the ‘atomic de-dispersion’ is non-pruned, while a translucent dashed black line or dotted red line indicate that it is pruned. The translucent dotted red line represents the pruned atomic de-dispersion in the final stage, which is not used as only sub-band data are needed.