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To verify the effectiveness of a higher order electromechanical sigma–delta modulator (ΣΔM), a micromachined accelerometer is fabricated. The in-plane sensor with fully differential structure has a mechanical noise floor below 1 μg Hz−1/2, static sensitivity 16 pF g−1 and resonant frequency 325 Hz. FEM analyses are performed to verify these key parameters. The silicon-on-glass sensor is fabricated by deep reactive ion etching (DRIE) and anodic bonding. Compared with a second-order electromechanical ΣΔM, which only uses the sensing element as a loop filter, here it is cascaded with additional electronic integrators to form a fifth-order electromechanical ΣΔM, which leads to better signal to quantization noise ratio (SQNR). This novel approach is analysed and system level simulations are presented. A printed circuit board (PCB) prototype of this high-order ΣΔM loop was built and tested. The experimental data agree well with the simulation results.

Abstract-Three distinct methods of reading multi-level crosspoint resistive states from selector-less RRAM arrays are implemented in a physical system and compared for read-out accuracy. They are: the standard, direct measurement method and two methods that attempt to enhance accuracy by computing cross-point resistance on the basis of multiple measurements. Results indicate that the standard method performs as well as or better than its competitors. SPICE simulations are then performed with controlled amounts of non-idealities introduced in the system in order to test whether any technique offers particular resilience against typical practical imperfections such as crossbar line resistance. We conclude that even though certain non-idealities are shown to be minimised by different circuit-level read-out strategies, line resistance within the crossbar remains an outstanding challenge.

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Abstract-This work reports on the design of novel closed-loop control systems for the sense mode of a vibratory-rate gyroscope based on a high-order sigma-delta modulator (61M). A low-pass and two distinctive bandpass topologies are derived, and their advantages discussed. So far, most closed-loop force-feedback control systems for these sensors were based on low-pass 61M's.Usually, the sensing element of a vibratory gyroscope is designed with a high quality factor to increase the sensitivity and, hence, can be treated as a mechanical resonator. Furthermore, the output characteristic of vibratory rate gyroscopes is narrowband amplitude-modulated signal. Therefore, a bandpass 61M is a more appropriate control strategy for a vibratory gyroscope than a low-pass 61M. Using a high-order bandpass 61M, the control system can adopt a much lower sampling frequency compared with a low-pass 61M while achieving a similar noise floor for a given oversampling ratio (OSR). In addition, a control system based on a high-order bandpass 61M is superior as it not only greatly shapes the quantization noise, but also alleviates tonal behavior, as is often seen in low-order 61M control systems, and has good immunities to fabrication tolerances and parameter mismatch. These properties are investigated in this study at system level.