Abstract: An example apparatus includes a power detector that is connectable to an output port of a device under test (DUT) to receive a first radio frequency (RF) signal or a first part of the first RF signal from the DUT. The power detector is configured to detect a power of the first RF signal or of the first part of the first RF signal. The apparatus includes an attenuator that is connectable to the outport port of the DUT and connectable to or connected to an input port of the DUT. The attenuator is configured to receive a second RF signal or a second part of the first RF signal from the DUT and to attenuate the second RF signal or the second part of the first RF signal to produce an attenuated RF signal for output to the input port of the DUT.