Calibration of lock-in amplifiers in the low-frequency range

A setup for the calibration of lock-in amplifiers in the low frequency range is presented. The setup is based on an uncalibrated voltage source, an ac voltmeter, and calibrated inductive and resistive voltage dividers. The measurand is the relative deviation of the lock-in amplifier reading from the calibrated applied voltage. Examples of calibration of a commercial lock-in amplifier in the 10 μV range, atA setup for the calibration of lock-in amplifiers in the low frequency range is presented. The setup is based on an uncalibrated voltage source, an ac voltmeter, and calibrated inductive and resistive voltage dividers. The measurand is the relative deviation of the lock-in amplifier reading from the calibrated applied voltage. Examples of calibration of a commercial lock-in amplifier in the 10 μV range, at frequencies of 17 Hz and 103 Hz, are given; the calibration uncertainty, relative to the instrument full- scale, is under evaluation and expected to be of the order of 10-4. frequencies of 17 Hz and 103 Hz, are given; the calibration uncertainty, relative to the instrument full- scale, is under evaluation and expected to be of the order of 10 -