This paper addresses the calibration of lock-in amplifiers in the low frequency range. A simple but effective calibration setup implemented at INRIM is described. This includes a stable low-voltage source, composed of a digital sine wave generator and a cascade of two voltage dividers, one inductive and one resistive. The magnitude error is the lock-in magnitude error, which can be determined with an uncertainty of the order of 10⁻⁴ or better, that is, two orders of magnitude lower than the typical lock-in accuracy specification. The system can operate with an input voltage from 0.1 V to 10 V and a frequency from a few hertz to about 1 kHz. The performances of the calibration setup were evaluated at 1 V and 10 μV at 20Hz and 103Hz and compared with those of another existing setup, implemented at METAS, through a direct comparison in the framework of an EURAMET research project.

本文介绍了低频范围内锁相放大器的校准。描述了一种在INRIM实施的简单但有效的校准设置。其中包括一个稳定的低压电源，该电源由数字正弦波发生器和由两个分压器（一个电感性和一个电阻性）组成的级联组成。幅度误差是锁定幅度误差，可以用10 ^-4量级的不确定度确定或更好，即比典型的锁定精度指标低两个数量级。该系统可以在0.1 V至10 V的输入电压和几赫兹至大约1 kHz的频率下工作。通过在EURAMET研究项目的框架中进行直接比较，在20 Hz和103 Hz的1 V和10μV下评估了校准设置的性能，并将其与METAS实施的另一现有设置进行了比较。