【作者】 李婷；

【导师】 刘颖力； 郭向阳；

【作者基本信息】 电子科技大学 ， 电子信息（专业学位）， 2023， 硕士

【摘要】 随着集成电路行业的高速发展,有关模数转换器(Analog to digital converter,ADC)的研究也越来越深入。在自然界中,我们能感受到的常见的声音信号、振动信号等,都是模拟量。想要利用数字技术对日常生活中的模拟信号做数字处理就需要模数转换器来实现。因此,有关模数转换器的研究也越来越深入。主要分为奈奎斯特型ADC和过采样ADC两大类,奈奎斯特ADC指的是在满足奈奎斯特准则采样的模数转换器,相比较奈奎斯特ADC,Sigma-Delta ADC能做到高精度的主要原因是利用过采样和噪声整形技术,在对其ADC系统设计时对调制器的设计是很关键的。Sigma-Delta ADC广泛应用于医疗、音频等高精度信号处理领域。论文比较了有关一阶调制器和二阶调制器以及高阶调制器等其他架构的调制器的特点,对Sigma-Delta ADC调制器结构以及相关参数进行了设计,以保证功能与指标的实现。通过MATLAB中的SIMULINK环境对调制器结构进行系统建模,优化了相关调制器系数,对Sigma-Delta调制器理想模型的输出结果做FFT分析,并加入各类非理想因素,通过调制器输出的结果来确定是否满足系统指标。根据得到的调制器系数来设计晶体管级电路,观察电路的输出,再反复调整优化调制器系数,从而得到电路可行性调制器结构。设计了一款应用于高精度音频Sigma-Delta ADC调制器,其中电路开关采用CMOS互补开关,利用互补技术极大消除开关存在的非线性,同时在第一级积分器加入斩波技术用来降低第一级积分器的失调和低频1/f噪声。调制器结构采用二阶多比特量化结构。采用二阶调制器结构可以保证调制器的稳定性要求。调制器设计结构采用smic 0.18um CMOS工艺,基于smic 0.18um工艺对结构进行电路级设计与仿真。在20～20kHz频率范围内信噪比达到98dB,有效位数可达16位。更多还原

【Abstract】 With the rapid development of the integrated circuit industry,research on Analog to Digital Converter(ADC)is becoming increasingly in-depth.In nature,the common sound signals,vibration signals,etc.that we can feel are analog quantities.To utilize digital technology for digital processing of analog signals in daily life,an analog-to-digital converter is required.Therefore,research on analog-to-digital converters is becoming increasingly in-depth.It is mainly divided into Nyquist ADC and oversampling ADC.Nyquist ADC refers to the analog-to-digital converter that meets Nyquist criterion sampling.Compared with Nyquist ADC,the main reason why Sigma Delta ADC can achieve high precision is that oversampling and noise shaping technology are used,and the design of modulator is critical when designing its ADC system.Sigma Delta ADC is widely used in high-precision signal processing fields such as healthcare and audio.The thesis compares the characteristics of modulators with other architectures such as first-order modulators,second-order modulators,and higher-order modulators,and designs the structure and related parameters of Sigma-Delta ADC modulators to ensure the implementation of functions and indicators.The modulator structure was systematically modeled using the SIMULINK environment in MATLAB,and the relevant modulator coefficients were optimized.FFT analysis was performed on the output results of the ideal model of the Sigma-Delta modulator,and various non ideal factors were added to determine whether the system indicators were met through the output results of the modulator.Design a transistor level circuit based on the obtained modulator coefficients,observe the output of the circuit,and repeatedly adjust and optimize the modulator coefficients to obtain a feasible modulator structure for the circuit.A high-precision audio Sigma-Delta ADC modulator has been designed,in which the circuit switches use CMOS complementary switches to greatly eliminate the nonlinearity of the switches.At the same time,chopping technology is added to the first stage integrator to reduce the offset and low-frequency l/f noise of the first stage integrator.The modulator structure adopts a second-order multi bit quantization structure.The use of a second-order modulator structure can ensure the stability requirements of the modulator.The modulator design structure adopts the SMIC 0.18um CMOS process,and the circuit level design and simulation of the structure are carried out based on the SMIC 0.18um process.In the frequency range of 20～20kHz,the signal-to-noise ratio reaches 98dB and the effective digits can reach 16 bits.更多还原