Fig. 6. Full measurement setup.

The outputs of the JPC are amplified in different stages before being down converted to 20 MHz using two local oscillators (LO₁ and LO₂). After the down-conversion, the signals are filtered and amplified once more and then digitized using an analog-to-digital converter (ADC). Classically CI is performed by using correlated white noise generated by an arbitrary waveform (noise) generator. For coherent-state illumination, we generate a coherent tone and send it to the refrigerator. The signal is reflected from the unpumped JPC and passes through the measurement chain.