Automatic Calibration of Frequency Response for AC Attenuators in Precision Voltage Measurements

ABSTRACT Conventional RC divider–based attenuators in precision AC voltage measurement are highly susceptible to parasitic parameters. This issue causes fluctuating attenuation ratios at high frequencies and degrades signal transmission accuracy. To address this, a novel calibration method is proposed to stabilize frequency response through capacitive compensation and feedback adjustment. A calibration model is first established by mapping the time‐ and frequency‐domain responses, explicitly accounting for real‐life parasitic effects. Guided by this model, an automatic frequency compensation system and a corresponding timing diagram are designed. The method is validated through simulation and experiment using a 100:1 AC attenuator for covering 300 V RMS measurement. Results demonstrate markedly improved performance: The low‐voltage (LV) attenuation achieves a response flatness of 0.43% in the 10 Hz to 100 kHz band and 0.59% in the 10 Hz to 1 MHz band, whereas the high‐voltage (HV) attenuation shows 0.68% flatness in the 10 Hz to 100 kHz frequency band. Additionally, the design exhibits excellent linearity better than 41 ppm and minimal temperature drift.