小信号放大电路任意波形THD全自动测量系统研究  

An automatic calculation system of arbitrary waveform THD for small signal amplification circuit

作　　者：桂丹 喻宗杰[3] GUI Dan;YU Zong-jie(Wuhan National Laboratory for Optoelectronics,Huazhong University of Science and Technology,Wuhan 430074;School of Electronic Engineering,Wuhan Vocational College of Software and Engineering,Wuhan 430205;FiberHome Telecommunication Technologies Co.,Ltd.,Wuhan 430205,China)

机构地区：[1]华中科技大学武汉光电国家研究中心,湖北武汉430074 [2]武汉软件工程职业学院电子工程学院,湖北武汉430205 [3]烽火通信科技股份有限公司,湖北武汉430205

出　　处：《计算机工程与科学》2022年第7期1199-1206,共8页Computer Engineering & Science

基　　金：湖北省教育厅2020年度科研计划(B2020405);武汉市产学研项目(CXY202014)。

摘　　要：总谐波失真THD是衡量信道非线性程度的重要指标,应用于音频小信号放大电路的任意输出波形识别和总谐波失真的全自动测量系统成为检测信号放大性能的有效手段。为准确计算放大后的波形总谐波失真度,采用了快速傅里叶变换FFT技术。从提高系统效率角度,使用高频率采样并半数提取的技术方案。通过动态控制继电器、阻容元件及多级放大等手段,合理调整放大系统静态工作点的位置和输入波形大小,实现不同类型的失真波形输出。基于stm32f103c6单片机,联动开关一键式完成任意波形采集、识别、计算和显示,极大提升了小信号放大电路失真度测量的工作效率。Matlab运算仿真、Multisim电路仿真及实物测试表明,多级晶体管放大一致性调节电路和单片机FFT运算组成的小信号放大电路任意波形THD全自动测量系统,可准确、实时识别波形并计算出总谐波失真,一键式切换设计操作方便、节约成本,颇具实用价值。Total Harmonic Distortion(THD)is an important index to measure the nonlinear degree of channel.The automatic measurement device applied in arbitrary output waveform identification and total harmonic distortion of the audio small signal amplification system has become an effective means to detect the signal amplification performance.In order to accurately calculate the total harmonic distortion of the amplified waveform,FFT technique is adopted.In order to improve the system efficiency,high frequency sampling and half extraction techniques are adopted.Dynamic control relays,resistance-capacitance components and multi-stage amplification are used to reasonably adjust the position of the static operating point of the amplification system and the size of the input waveform to realize the output of different types of distorted waveforms.Based on microcontroller stm32f103c6,the combination switch completes the collection,identification,calculation and display of arbitrary waveform in one-button,greatly improving the working efficiency of small signal amplification systems.Matlab algorithm simulation,Multisim circuit simulation and practical test show that,the automatic calculation device of arbitrary waveform THD for small signal amplification systems consisting of multi-stage transistor amplification consistency adjustment circuit and microcontroller FFT operations can accurately and real-time identify waveforms and calculate THD.The one-button switching design is convenient to operate,saves cost,and has practical value.

关 键 词：多级放大电路 增益控制 总谐波失真 傅里叶变换 系统设计 电路仿真 

分 类 号：TP35[自动化与计算机技术—计算机系统结构]