单片集成R／D转换及数字处理技术研究与设计

摘要

This paper introduces the design method of R/D conversion technology and products. A novel Implementation of the digital R/D converter combining digital signal processing technology with sigma⁃delta (Σ-Δ) ADC is established. The typical structure of Σ-Δ ADC is optimized to fit for the requirement of real⁃time data processing. The digital phase sensitive detection is acquired by calculating the cross correlation function of internal synthetic reference sequence and digital signal sequence of Σ-Δ modulator. To realize fast conversion, the digital processing and filtering circuit in ADC are integrated into the type 2 tracking closed⁃loop system. This method can simplify circuit structure and reduce chip size. The RTL code of dig⁃ital integrator and filter are designed in Verilog language. The proposed design is verified by mixed⁃signal simulation. The co⁃simulation method based on MATLAB/Simulink and Cadence is used to analysis convertor output spectrum. Finally, a practi⁃cal circuit for R/D converter is described. The experiments results show that the presented method is effective and the per⁃formances of the R/D convertor come up to the level of the same products from abroad.%介绍了R／D转换技术及单芯片产品的设计方法。探讨采用数字信号处理技术和Σ－ΔADC（模数转换器）实现数字R／D转换的方法。为满足系统的实时数据处理要求，对典型的Σ－ΔADC结构进行了改进，将Σ－Δ调制器得到信号的数字序列，通过内部合成正弦波序列和信号序列的互相关函数实现数字相敏检测。将ADC中的数字处理及滤波电路融合到R／D解算的2型闭环系统中，实现快速转换，简化了电路设计并有效降低芯片面积。数字积分及滤波器采用Verilog语言编写的RTL级代码，采用数模混合仿真实现R／D的整体电路验证。通过Matlab与cadence软件协同仿真方法对转换数据进行频谱特性分析。最后，给出了实际设计的R／D转换电路，实验结果表明，研制单芯片产品的性能指标与国外产品相同。