Calibration of lock-in amplifiers

Project Description

Methods for the calibration of the gain of a digital lock-in amplifier in the low frequency  (<100 Hz) range and for voltage range between 1 and 100 µV are investigated.
The measurements aim to the mutual validation of the different methods with a travelling standard.

Final Report 2021-01-18

The EURAMET TC-EM Project 1466 “Calibration of lock-in amplifiers” concerned the mutual validation of the performance of the two new setups respectively developed at METAS and INRIM.

These new setups for the calibration of lock-in amplifiers in the low frequency range (below 1kHz) allow to determine the lock-in magnitude error with an uncertainty of the order of 1e-4 or better, that is, two orders of magnitude lower than the typical accuracy from factory specifications.

In February 2020 the INRIM setup was moved to METAS for on-site measurements. The results and discussion of the comparison have been published, along the description of the new INRIM setup, in: A. Cultrera et al., “A new calibration setup for lock-in amplifiers in the low frequency range and its validation in a bilateral comparison”, Metrologia, 2021, DOI: 10.1088/1681-7575/abdae0

The outcome of this project represents an advantage for many users interested in applications where lock-in amplifiers are employed as measurement instruments.

Progress Report 2020-02-26

The project partners investigated two different methods for the calibration of the gain of a digital lock-in amplifier. The INRIM calibration system was moved to METAS in the period 4 to 7 February 2020. The INRIM and METAS systems were employed to calibrate two lock-in amplifiers (Stanford Research SR850) on their 1 μV and 10 μV scales at two different frequencies (20 Hz and 103 Hz).

Data processing and final reporting is ongoing.