高精度Sigma-Delta调制器设计

发布时间：2018-05-01 18:02

本文选题：Sigma-Delta调制器 + 一位量化　；参考：《哈尔滨理工大学》2015年硕士论文

【摘要】：硅微机械陀螺作为惯性传感器大家族中的重要一员，无论在我们的日常生活中，或是工业生产中，甚至在军工业上都不乏它的身影。其凭借着高精化、集成化、低能耗的特点已经成为了各大实验室和研究所的科研重点。而Sigma-Delta调制器作为硅微机械陀螺中的接口模块重要组成部分，不同于传统调制器，它拥有更高的信噪比，在高精度模数转换器上有着长足的发展。本文针对硅微机械陀螺设计了一种四阶前馈型Sigma-Delta调制器。其高精度的特性满足了硅微机械陀螺接口模块的设计要求。Sigma-Delta调制器高信噪比主要归功于噪声整形技术和过采样技术。通过增加采样频率降低带内的量化噪声功率，由于Sigma-Delta调制器传递函数本身具有的低通特性，能够将量化噪声调制到高频处经滤波器滤器，提高了精度。时钟馈通效应和电荷注入效应是影响开关非理想特性的主要因素，通过开关上体端短接的补偿结构可以使得方向等量电荷注入，有效抑制电荷注入效应。全差分放大器结构能够抑制偶次谐波、时钟馈通效应、噪声等影响，高精度的Sigma-Delta调制器代表运算放大器要拥有足够的增益，四阶Sigma-Delta调制器一般需要40dB的直流增益。通过MATLAB软件中的Simulink建立非理想模型并通过仿真结果验证方案可行性。本课题采用信号带宽20kHz，采样频率为10.24MHz。首先得到其理想模型情况下的的信噪比为145.5dB，其有效位数为23位。通过加入非理想因素模型，得到的有效位数仍为20位，噪底低于-140dB，证明该系统方案满足设计需求。在对系统电路进行整体设计之后，在Cadence软件下对本设计进行仿真，得到本调制器有效位数为16位，噪底低于-120dB，，谐波淹没在噪底当中，满足设计要求。
[Abstract]:Silicon micromachined gyroscope is one of the most important members of inertial sensor family. It is not only in our daily life but also in industrial production and even in military industry. With the characteristics of high precision, integration and low energy consumption, it has become the scientific research focus of various laboratories and research institutes. As an important part of interface module in silicon micromachined gyroscope, Sigma-Delta modulator is different from traditional modulator. It has higher signal-to-noise ratio (SNR), and has a great development in high precision analog-to-digital converter (ADC). In this paper, a four-order feedforward Sigma-Delta modulator is designed for silicon micromachined gyroscope. Its high precision characteristics meet the design requirements of the interface module of silicon micromachined gyro. The high signal-to-noise ratio of Sigma-Delta modulator is mainly attributed to noise shaping technology and oversampling technology. By increasing the sampling frequency to reduce the quantized noise power in the band, the quantization noise can be modulated to the filter filter at the high frequency because of the low pass characteristic of the transfer function of the Sigma-Delta modulator, which improves the accuracy. Clock feed-through effect and charge injection effect are the main factors that affect the non-ideal characteristics of the switch. The directional charge injection can be effectively suppressed by the short junction compensation structure of the upper end of the switch. The structure of fully differential amplifier can suppress the influence of even harmonic, clock feedthrough effect, noise and so on. The high precision Sigma-Delta modulator represents that the operational amplifier must have enough gain, and the fourth order Sigma-Delta modulator generally needs the DC gain of 40dB. The non-ideal model is established by Simulink in MATLAB software and the feasibility of the scheme is verified by simulation results. The signal bandwidth is 20 kHz and the sampling frequency is 10.24 MHz. The signal-to-noise ratio (SNR) of the ideal model is 145.5 dB and the effective bit number is 23 bits. By adding the non-ideal factor model, the effective bit number is still 20 bits and the noise base is lower than -140 dB, which proves that the system scheme meets the design requirements. After the overall design of the system circuit, the design is simulated under the Cadence software. The effective bit number of the modulator is 16 bits, the noise base is lower than -120dB, and the harmonics are submerged in the noise bottom, which meets the design requirements.
【学位授予单位】：哈尔滨理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN761

【参考文献】