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中文摘要: 针对MEMS传感器输出电压小并且频率低的特点，本文设计了一种低噪声嵌套斩波Σ-Δ调制器。该调制器采用单环积分器级联前馈（CIFF）结构与嵌套斩波技术结合，降低了传感器接口电路的低频噪声，并减小了CMOS电路中斩波开关引入的残余失调电压。仿真结果表明，本文提出的嵌套调制器可以有效抑制低频噪声。采用嵌套斩波Σ-Δ调制设计，在100 Hz信号带宽内，调制器最高信噪比达到109dB，即17.8 bits的有效位数，满足了MEMS传感器低频微弱信号检测的要求。
Abstract:A low-noise sigma-delta (Σ-Δ) modulator, which uses nested-chopper technique, is designed for MEMS sensor with low-frequency weak output voltage. The proposed modulator combines cascade integrators feed forward (CIFF) architecture with nested-chopper technique. The inherent low frequency noise in the sensor interface is eliminated, and the residual offset introduced by CMOS chopper switches is also reduced. Simulation results show that the nested-chopper Σ-Δ modulator presented in this paper can restrain the low-frequency noise. The nested-chopper Σ-Δ modulator achieves a peak signal-to–noise ratio of 109 dB over a bandwidth of 100 Hz, equaling to a resolution of 17.8 bits, satisfying the requirement of MEMS sensor with low-frequency weak output voltage.
文章编号：cg13000201 中图分类号： 文献标志码：
基金项目:863项目、973项目
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