A frequency conversion device for transforming a frequency of an input signal, the device comprising: a signal generator for providing a plurality N of first signals at a first frequency, where N≧1, from an input signal having an in-phase component I and a quadrature signal component Q; an oscillator for generating N parallel oscillation signals, wherein the N oscillation signals are stepped in phase with respect to one another; a mixer comprising N mixing components, each mixing component being coupled to receive a respective one of the plurality of first signals and coupled to receive a respective oscillation signal for mixing the respective first signal with the corresponding oscillation signal to provide an output signal; and a common amplifier for receiving the N output signals from the N mixing components in N sequential phases for transmission.