A Bridge-Balancing Circuit for Balanced Measurement of Resonant Sensors

Digital Eddy Current Detection Method Based on High-Speed Sampling with STM32

“…According to the differential amplifier circuit equations [ 24 , 25 ], when , the output of the amplifier is (where is the input at the negative terminal, and is the input at the positive terminal), at which point the common-mode rejection ratio of the amplifier approaches infinity. The advantage of using an AC differential bridge lies not only in doubling the sensitivity of the system but also in providing temperature compensation.…”

“…Considering that the bridge output signal is small and may contain substantial common-mode noise, it is necessary to amplify the bridge output signal using an instrumentation amplifier before it can be acquired by the AD converter. According to the differential amplifier circuit equations [24,25], when…”

“…The values d 11 , d 22 , and d 33 in Equation ( 22) are the diagonal values in matrix M, which is described by Equation (24). The standard deviations σ A and σ φ for the fitted amplitude and phase can be synthesized through the function's standard deviation with the synthesis formula provided in Equation (25). The specific expressions for A(a, b) and Φ(a, b) in the formula have already been defined in Equation (12).…”