A method for measuring characteristics of a transmitter unit of a device under test is described. A signal generator is provided that comprises a baseband processing unit having at least a digital pre-distortion sub-unit. A device under test is provided that has a transmitter unit. A measuring unit is provided. Said signal generator and said device under test are connected with each other via an interface. At least one input signal is generated by using said signal generator, said input signal is forwarded to said device under test. An output signal of said device under test is measured by using said measuring unit. A first pre-distortion parameter for increasing input amplitude is determined by using said digital pre-distortion sub-unit. A second pre-distortion parameter for decreasing input amplitude is determined by using said digital pre-distortion sub-unit. Said first and second pre-distortion parameters are determined such that said output signal has a high fidelity. Further, a test system and a radio frequency device are described.