A mixer circuit (200, 300, 800, 900) for mixing a first input signal at a first frequency with a second input signal at a second frequency to an output signal at a third frequency. The mixer circuit (200, 300, 800, 900) comprises a mixing stage (205, 805) with differential input ports (206, 207; 820, 821) for the first input signal and an input port (211, 911) for the second input signal and differential output ports for the output signal, which also serve as output ports for the mixer circuit. The mixer circuit (200, 300, 800, 900) comprises a nonlinear digital to analogue converter (210, 810) which has an input port (211) which is the input port for the second input signal and an output port (212) which is connected to the input port of the mixing stage, and the digital to analogue converter has a nonlinear transfer function.