The typical properties of an RF signal is that it has a limited spread in frequency, that is it is limited to a certain frequency band. This implies that the RF signal has a long distribution in time. A typical signal consists of several tones (frequency bands) that are recorded one by one or all as a bunch. At the input of the digitizer is a signal with very high bandwidth to cover the frequency up to RF frequency. The RF signal of interest has often a limited bandwidth which means that a DDC can be used for reducing the data rate to the signal band of interest. Important digitizer parameters for RF measure are high bandwidth, high dynamic range, DDC-firmware.