In this paper, we propose a method to quantify the non-linearity of the quantizer, which is one of the key nonlinear blocks in Delta-Sigma analog-to-digital converter (ΔΣ ADC) and the only one that is inherently nonlinear. By deriving the histogram of the components at the quantizer input other than the signal, it is possible to quantify the effective non-linearity in ΔΣ ADC, and quantify the effect of scaling factors such as the gains of the integrators on non-linearity. Quantizer non-linearity is evaluated through numerical calculations, complemented by analytical investigations with practical approximations. The comparison with the behavioral simulation results demonstrates the feasibility of the proposed analysis.

There is an increasing request for interfacing high input common mode (CM) voltages in voltage or current sense such as battery management system. This paper proposes a capacitive gain amplifier (CGA) designed to sample the differential mode (DM) voltage of signals with a CM voltage that varies from 0 to 90V. A control strategy that integrates chopping and auto zero (AZ) is used to reduce the input offset voltage. This control strategy also accelerates the CM voltage establishment of the CGA. A high-voltage switch (HV Switch) has been designed to ensure that the CM voltage of the input signal reaches 90V, while the DM voltage reaches 5V. A linear trim method is proposed to reduce gain error. The CGA has been manufactured in the DBhitek 0.18-μm CMOS process. As the Vcm varies from 0 to 90V, the circuit has an offset voltage of 3.8μV, an output noise of 71.8nV/Hz^1/2 and a gain error of 0.0056%.

Optical correlation-domain reflectometry (OCDR), widely recognized for its ability to pinpoint the locations and reflectivities of faulty connections and other reflective points along optical fibers, offers the advantages of random accessibility, real-time operation, and cost-effectiveness. In Brillouin OCDR, commonly employed for distributed strain and temperature sensing, a well-known challenge is the trade-off between spatial resolution and measurement range. To overcome this limitation, a double-modulation scheme has been introduced. Recent research has shown that this trade-off is also present in simplified OCDR systems without a frequency shifter, making it crucial to develop methods that can extend the measurement range while preserving spatial resolution. In this study, we experimentally validate the ability of the double-modulation scheme to effectively enhance the measurement range in simplified OCDR.