The new temperature controller model 54 from CryoCon can now measure impedance and inductance at low temperatures. In addition, it comes with four outputs for temperature control.
Each of the four input channels uses a CryoCon proprietary signal processing chip which measures impedance by utilizing a special AC bridge. Here, advanced signal processing functions are integrated, thus replacing large numbers of analog circuitry with more sophisticated digital algorithms and higher precision.
Impedance measurements in cryogenic systems often require low-level excitation and precise signal recovery. To implement this, Model 54 uses a differential voltage-mode excitation scheme followed by bi-phase lock-in detection.