基于FPGA的失真度测试仪设计（毕业论文）.docVIP

摘 要 在电子工程的设计和应用中，信号无论在开路传输或闭路传输过程中都受到环境、传输网络的工作状态和应用元器件参数变化的影响使其或多或少的改变了原有信号的性质，这种变化就是所谓的信号畸变现象，通常叫做失真。信号的失真分为三种:频率失真，相位失真和波形失真。波形失真又称非线性失真，它是由放大电路的非线性引起的，非线性失真又包括谐波失真和互调失真。 　　通过非线性失真测试可以考察传输网络的失真性质，有利于改进传输网络的性质。因此在信息产生，传递，接受过程中，必须认真分析处理好失真问题。各种非线性失真测试仪在电力、电子、通信领域中得到广泛应用。常用的失真度检测仪器按测量原理大致可分为二大类:基波剔除法和频谱分析法。一般模拟式的测量仪采用基波剔除法，其缺点是需要提供未失真的基波信号而且其低频测量精度低。频谱分析法是用频率分析仪测量各次谐波的方法计算出波形失真度，但采用此种方法的仪器价格较昂贵。 随着微型计算机、单片机尤其是数字处理芯片DSP的发展与应用，本文提出了一种基于DSP芯片的采用快速傅立叶变换(FFT)算法，计算出信号基波及各次谐波的电压有效值，从而根据失真度计算公式计算失真度的测量方法。论文首先介绍国内外传统失真度分析仪的测量方法及应用前景，然后对几种测量方案进行比较并选择较好方案，然后进一步阐述并分析该方案的硬件实现和软件实现及其matlba仿真结果，接着对该方案的软硬件测量误差进行分析，最后是全文的总结。 关键词：FFT； FPGA； 失真度 Abstract In the design and application of electronic engineering， bothcircuit， signalenvironment， theapplied. Then the characters of useful information will be changed more or less and the change is generally called as distortion， namelydistortion. Signal distortion includes three kinds of distortion: frequency，phasecircuits it is often called as nonlinearity distortion. The nonlinearity distortion also include harmonic distortion and intermodulation distortion. We can test the charater of the transport newtok by detecting the nonlinear distortion and this is useufl to improve the character of the newtork. In the generation，transport and reception of singal，we must careuflly analyze and handle distortion. Kinds of nonlinear distortion meters have been widely used in many fields such as electronies，electricity and communication，and so on.The distortion meters used in common generally be divide in tow kinds as the method of theory of test. They are the method of suppressed first frequency and the method of frequeney table analysis. Most of analog distortion meters apply the method of suppressed fisrt frequency. But the disadvantages are need to suppply the first frequency and the lower test precision of the low frequency.The method of analysis frequency table is using the meter of frequency table to test all kinds of frequency and then c