Accurate Measurement of the RMS Value by Means of an Analog Multiplier-based RMS-to-DC Converter

摘要

This paper investigates the influence of the accuracy of the op-amp used by the square root circuit on the accuracy of the root mean square (rms) measurement achieved by means of an analog multiplier-based rms-to-dc converter implemented using the direct method. The rms measurement accuracy achieved using the internal op-amp of the multiplier is compared through experimental results with that achieved using more accurate op-amps, namely TL082 and OPA277. The analyzed rms-to-dc converter is implemented using the Texas Instruments Analog System Lab Kit (ASLK) PRO board equipped with MPY634 analog multipliers. The experimental data are obtained by means of a dedicated experimental setup.