软硬协同实现基于ARM Cortex-M4平台的信号采样与重构

Realization of ARM Cortex-M4 platform based signal sampling and reconstruction by software-hardware cooperation

为了探究音频信号实时处理的方法和效果,文中以Cypress的FM4 ARM Cortex-M4 MCU入门套件、信号源和示波器构成实验硬件平台。在此基础上,利用Keil MDK-ARM编程工具并结合微控制器软硬协同的特点,分析不同采样频率对数字信号处理中系统带宽的影响,以加深学生对奈奎斯特采样定理的理解,更好地掌握编码解码器在数字信号处理系统中实现模/数转换和数/模转换功能的基本方法。通过观察数字处理过程中信号采样可能产生的混叠现象,引导学生认识数字处理系统中抗混叠滤波器和重建滤波器设计的重要性及其特性。基于该实验平台,学生可以快速面向应用进行项目开发,增强理论应用能力和综合实践能力。文中通过构造一个富有启发性且难易适中的包含硬件开发、软件仿真和算法实现的实验环节,实现验证性、综合性和演示性的统一。

In order to investigate the method and effect of real-time processing of audio signals,the experimental hardware platform is composed of FM4 ARM Cortex-M4 micro control unit(MCU)starter kit of Cypress,signal source and oscilloscope.The influence of different sampling frequencies on system bandwidth in digital signal processing is analyzed by means of the Keil MDK-ARM programming tool and in combination with collaborative characteristics of software and hardware of microcontroller,so as to deepen students understanding on Nyquist sampling theorem and better master the basic methods to implement the analog-to-digital conversion and digital-to-analog conversion by codec in digital signal processing system. By observing the aliasing phenomenon that may be produced by signal sampling in the process of digital processing,it is important to guide students to recognize the importance and characteristics of anti-aliasing filter and reconstruction filter design in digital processing system. Based on the experimental platform,students can rapidly develop projects for applications,which can enhance their abilities of theoretical application and comprehensive practice. A heuristic and moderately difficult experimental link including hardware development,software simulation and algorithm implementation is constructed to achieve the unity of verifiability,comprehensiveness and demonstration.