Pulse width modulation type Josephson AC waveform synthesizer

The operation principle of a digital-to-analogue conversion (DAC) for an accurate AC waveform synthesis based on a pulse width modulation (PWM) of an output voltage of an overdamped Josephson junction (JJ) array is considered. The PWM of the voltage is achieved by the PWM of a sine microwave JJ array bias at a constant DC bias. A set-up realizing the above method is described. To illustrate the synthesizer operation principle, JJ array I-V curves at two microwave power levels and an example of the PWM voltage signal are shown.