<p>A device (100) for generating an output signal (So) having substantially same or increased output frequency compared to an input frequency of an input signal (Si), the device (100) comprising: a bipolar transistor (102) having a base (B), a collector (C), and an emitter (E); a control unit (104) adapted for controlling application of the input signal (Si) to the base (B) and adapted for controlling application of a collector-emitter voltage between the collector (C) and the emitter (E) in a manner for operating the bipolar transistor (102) in a snap-back regime to obtain a non-linear collector current characteristic to thereby generate the output signal (So) having the substantially same or increased output frequency resulting from a steeply rising collector current.</p>
