In one embodiment, at least one parameter set for at least one harmonic of a continuous wave (CW) signal is digitally generated in response to a parameter set for the CW signal. In response to the parameter set for the CW signal, the CW signal is synthesized; and in response to the at least one parameter set for the at least one harmonic of the CW signal, at least one nulling tone is synthesized. The CW signal and the at least one nulling tone are amplified; and the amplified CW signal and the at least one amplified nulling tone are summed to produce a linearized amplified CW signal. Other embodiments are also described.