Fig. 2: Schematic drawing of the measurement circuit.
From: Single-electron detection utilizing coupled nonlinear microresonators
a Open-loop experiment. b Closed-loop experiment. The orange part represents the same differential circuit used in the open-loop experiment. The green dotted line block represents some necessary function modules in the HF2LI LIA. The purple dashed line block shows a method to create an equivalent feedthrough signal by utilizing a capacitor and phase shift
