Ratio-to-phase conversion method for drift-free physical measurement.

2014 Fiscal Year Final Research Report

• Project/Area Number: 24656062
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Applied physics, general
• Research Institution: Osaka University
• Principal Investigator: KATSURA Makoto 大阪大学, 理学(系)研究科(研究院), 助教 (70304003)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: ドリフト / 電圧計測 / 高調波 / 非線形性低減

Outline of Final Research Achievements

A new method, ratio-to-phase conversion, was developed for determining the ratio of the voltage to be measured (S) and the nominally constant voltage reference (R). A stepwise signal was generated at the carrier frequency (fc) by cyclic switching R, S and the ground level. This signal is found to be useful because the gain and the offset of the voltmeter can be easily corrected as a two-point calibration. We adopt the phase calculation at fc as the method to realize such calibration. Third order harmonic is found to be useful to eliminate the effect of the time delay of the voltmeter on the phase.
Also, harmonics cancellation in the stepwise signal is proved to be a new method to reduce the non-linearity of the voltmeters.

Free Research Field

地球物性学