基于数字PWM发生器的非对称双边沿UPWM信号频谱分析  

Spectral analysis of asymmetric double edge UPWM signal based on digital PWM generator

作　　者：陈晓雷[1] 张恩光 于泽琦[1] CHEN Xiao-lei;ZHANG En-guang;YU Ze-qi(School of Computer and Communication Engineering,Zhengzhou University of Light Industry,Zhengzhou 450000,China)

机构地区：[1]郑州轻工业学院计算机与通信工程学院

出　　处：《电子设计工程》2019年第16期33-38,共6页Electronic Design Engineering

基　　金：国家自然科学基金资助项目(61601411);河南省重点研发与推广专项(科技攻关)项目(192102210243,182102210607,192102210108)

摘　　要：数字脉冲宽度调制(Pulse Width Modulation,PWM)发生器是数字D类音频功放的核心模块。由于数字PWM发生器的输入信号是数字信号,无法利用双重傅里叶级数估计数字PWM发生器输出的均匀采样脉冲宽度调制(Uniform-sampling Pulse Width Modulation,UPWM)信号的频谱。针对该问题,本文基于UPWM信号的时域特征,提出一种当调制信号是数字信号时得到的非对称双边沿UPWM信号的频谱估计模型。利用现场可编程门阵列(Field-Programmable Gate Array,FPGA)搭建了一个数字PWM发生器,通过测量该数字PWM发生器输出信号的频谱,并将实际测量结果与所提频谱估计模型对比,验证了所提频谱估计模型的正确性。最后,利用所提频谱估计模型,给出非对称双边沿UPWM信号的失真度与输入信号量化等级的关系。The digital Pulse Width Modulation(PWM)generator is the core module of the digital class- D audio power amplifiers. Since the digital PWM generator input is a digital signal,the frequency spectrum of the digital PWM generator output Uniform- sampling Pulse Width Modulation(UPWM) signal cannot be estimated by double Fourier series. Based on the discrete Fourier transform technique, this paper proposes a spectrum estimation model for asymmetric double edge UPWM signal obtained when the modulation signal is a digital signal. A digital PWM generator is built by using Field- Programmable Gate Array(FPGA). The frequency spectrum of the digital PWM generator output signal is measured. The actual measurement results are compared with the proposed spectrum estimation model to verify the correctness of the proposed spectrum estimation model. Finally,by using the proposed spectrum estimation model,the relationship between the distortion of asymmetric double edge UPWM signal and the quantization level of input signal is given.

关 键 词：数字脉冲宽度调制发生器 离散傅里叶变换 频谱估计 总谐波失真 量化等级 

分 类 号：TN911.6[电子电信—通信与信息系统]