Example of RFI mitigation with SKF, ZDMF, and KF. The test data used are from MMGPS-L and have 2048 frequency channels with a time resolution of 153 us. The SKF, ZDMF, and KF are applied successively to the raw data. The top-left panel displays the dynamic spectrum of the raw filterbank data. The top-right panel shows the dynamic spectrum of the data after application of the SKF, which removes the bad frequency channels. The bottom-left panel shows the dynamic spectrum of the data after application of the ZDMF, which eliminates zero-DM RFI signals and the baseline variation. Finally, the bottom-right panel shows the dynamic spectrum of the data after application of the KF, which removes long-duration RFI signals.