A device for OOK modulating an input signal, comprising at least: an injection-locked oscillator comprising a power supply input, an injection signal input and an output to which the OOK modulated signal is to be delivered; a first controlled switch comprising a control input to which the input signal is to be applied, and configured to couple or not a power supply source to the power supply input of the injection-locked oscillator in dependence on the value of the input signal; a periodic signal providing device configured to deliver, on an output which is electrically coupled to the injection signal input of the injection-locked oscillator, a periodic injection signal whose frequency and amplitude trigger locking of the injection-locked oscillator at the frequency of the injection signal or a multiple of this frequency.