An apparatus (10) is disclosed for testing a receiver (18). The apparatus (10) includes a digitally controlled attenuator (30) and controls, including a programmable logic device (38), to control both the final value of attenuation and the rate of change of attenuation from the initial attenuation value in the attenuator (30) to the final value of attenuation. Both the final value of attenuation and the rate of change of attenuation can be selected by the operator on the control panel (20) with attenuation select switches (22) and rate select switch (26). Alternatively, the attenuation can be input with an attenuation control knob (28). A digital display (24) displays the attenuation. The apparatus (10) can be remotely controlled with a GPIB control.