A frequency changer for a radio frequency tuner and a tuner incorporating such a frequency changer are provided. The frequency changer comprises a mixer comprising a plurality of mixing stages. The output signals of these stages are supplied without relative phase shift to a summer, for example, in the form of a common load arrangement. The inputs of the stages are connected together to form a signal input of the mixer. Commutating signal inputs of the mixing stages received from the local oscillator are of the same frequency, but of different phases. The commutating signals are square or rectangular waves.