数字滤波器 毕业论文外文翻译.doc

附录a：英语引文及翻译digital filterswalt kester.abstract:fir filter fir (finite impulse moisturiser response) filter: finite length unit impulse response filter， is the most basic element in a digital signal processing system， it can ensure that any amplitude frequency characteristics of strict linear phase frequency characteristics at the same time， at the same time the unit sample response is limited long， thus filter is stable system. therefore， fir filter in communication， image processing， pattern recognition and other fields have a wide range of applications.keywords: fir filter digital filter is one of the most important part of digital signal processing， almost appeared in all digital signal processing system.digital filter is to point to complete the function of the signal filtering processing， with limited accuracy algorithm of discrete time linear time-invariant system， its input is a set of (by the analog signal sampling and quantization) digital quantity， its output is a transformation of another set of numbers.compared with analog filters， digital filter without drift， able to handle low frequency signal， the frequency response can be made very close to the ideal characteristics， and can reach high precision， easy integration and so on， these advantages determine the application of digital filter is more and more widely.working principle: before entering the fir filter， the first to transform signal by a/d device module， the analog signals into digital signals; in order to make the signal processing can not occur distortion， the signal must satisfy is the nyquist sampling speed of a specific reason， generally take signal frequency limit of 4-5 times as the sampling frequency; generally available high speed of successive into type a/d converter， whether used by accumulative method or distributed algorithm to design fir filter， filter output data are a string of sequence， to enable it to intuitively reflected， still need through d/a conversion， thus composed of fpga fir filters output must be d/a converter module. fpga has a well-organized internal logic array and rich connection resources， particularly suitable for digital signal processing tasks， relative to the serial port operation as the leading general dsp chip， its better parallelism and scalability， using fast algorithm of fpga by accumulation， can design a high speed fir digital filter.hardware category: the hardware realization of fir filter has the following several ways:integrated circuit: is a kind of digital filter commonly used in monolithic integrated circuit， the circuit is simple to use， but because of the word length and the specifications of the order number is less， not easy to fully meet the actual needs. although multiple extension can be used to meet the requirements， but will increase the volume and power consumption， thus limited in practical application.dsp chip another is the use of dsp chip. dsp chip is a dedicated digital signal processing function can call， or according to the structure of the chip instruction set design code can realize the function of fir; with fir design when the coefficient calculation and its quantification is more complex， therefore generally uses the matlab software as cad， calculate the coefficient of fir; then for code design implementation. realization of fir filter is relatively simple， but because of program order execution， the speed is restricted. and different system of dsp chip is the same company， its programming instructions will also vary， development cycle is long.programmable another is the use of programmable logic device， fpga/cpld. fpga has the rules of the internal logic of array and rich resources of attachment， especially suitable for fine grain and high parallelism of the structure of the fir filter implementation， relative to the serial operation of general purpose dsp chip， parallelism and scalability are better. the characteristics of finite length unit impulse response (fir) filter has the following features: (1) the system of unit impulse response h (n) in a finite number of n value is zero (2) the system function h (z) in the | z | 0 convergence， the poles all at z = 0 (causal system) (3) the structure of the main is a recursive structure， there is no output to the input feedback， but some of the structures (such as frequency sampling structure) also contains a recursive part of feedback. a fir filter unit impulse response h (n) for a sequence of n point 0 n n - 1 or less， or less filter system function h (z) = h (n) * z - n that is， it has (n - 1) order pole at z = 0， has a limited (n - 1) a zero in any position of the z plane.the basic structure fir filter has the following basic structure: cross-sectional shape (7.10) of the expression system of difference equations y (n) = h (m) x (n， m) (7.11) obviously， this is the convolution of the linear shift invariant system and formula， also delay chain lateral structure of x (n)， as shown in figure 4 to 11， referred to as the transverse structure or convolution model structure， also known as direct type structure. used in figure 4 to 11 will be transposed theorem， available figure 4-12 transpose structure directly. figure 7.11 cross sectional type structure of fir filter cascade type h (z) is resolved into multiplication of coefficient of second-order factors (7.12) said one n / 2 take the integer part of n / 2. if n is even， it is an odd number of n - 1， so the coefficient has a zero in the b2k， this is because， at this time there are an odd number of root， the conjugate complex roots into the will is even， there must be an odd number of real root. figure 7-13 draw n is odd， cascade structure of fir filter， each a second-order factor in figure 4-11 horizontal type.the structure of each section to control a pair of zero， and then the need to control transmission zeros， it can be used. but this structure need coefficient b2k (i = 0， k = 1， 2，.， n / 2) than convolution model coefficient of h (n)， and the required number of multiplication also more than convolution model.译文数字滤波器科斯特奥特摘要：fir(finite impulse response)滤波器：有限长单位冲激响应滤波器，是数字信号处理系统中最基本的元件，它可以在保证任意幅频特性的同时具有严格的线性相频特性，同时其单位抽样响应是有限长的，因而滤波器是稳定的系统。因此，fir滤波器在通信、图像处理、模式识别等领域都有着广泛的应用。关键词:fir 滤波器 数字滤波器是数字信号处理中最重要的部分之一，几乎出现在所有的数字信号处理system.digital滤波器是指完成信号滤波处理的功能，用有限精度算法的离散时间线性非时变系统，其输入是一组(由模拟信号采样和量化)数字量，其输出是一个变换的另一组numbers.compared模拟滤波器，数字滤波器没有漂移，能够处理低频信号，频率响应可以非常接近于理想的特性，并且可以达到精度高，容易集成等，这些优势决定了数字滤波器的应用越来越广泛。工作原理： 在进入fir滤波器前，首先要将信号通过a/d器件进行模数转换，把模拟信号转化为数字信号；为了使信号处理能够不发生失真，信号的采样速度必须满足乃奎斯特定理，一般取信号频率上限的4-5倍做为采样频率；一般可用速度较高的逐次逼进式a/d转换器，不论采用乘累加方法还是分布式算法设计fir滤波器，滤波器输出的数据都是一串序列，要使它能直观地反应出来，还需经过数模转换，因此由fpga构成的fir滤波器的输出须外接d/a模块。fpga有着规整的内部逻辑阵列和丰富的连线资源，特别适合于数字信号处理任务，相对于串行运算为主导的通用dsp芯片来说，其并行性和可扩展性更好，利用fpga乘累加的快速算法，可以设计出高速的fir数字滤波器。硬件分类：fir滤波器的硬件实现有以下几种方式：集成电路: 一种是使用单片通用数字滤波器集成电路，这种电路使用简单，但是由于字长和阶数