DSP_学习报告_定点FIR滤波器的仿真和实现.docVIP

DSP学习总结 变量的作用域以及生存期CMD文件，要求熟悉DSP的存储器结构。Q格式等的应用matlab的运用。 （1） 由此得到系统的差分方程： （2） 若FIR 数字滤波器的单位冲激响应序列为h(n)，它就是滤波器系数向量b(n)。传统的滤波器分析与设计均使用繁琐的公式计算，改变参数后需要重新运算，从而在分析与设计滤波器尤其是高阶滤波器时工作量特别大。这里应用MATLAB 设计FIR滤波器，根据给定的性能指标设计一个H(z)，使其逼近这一指标，进而计算并确定滤波器的系数b(n)，再将所设计滤波器的幅频响应、相频响应曲线作为输出，与设计要求进行比较，对设计的滤波器进行优化。设计完成之后将得到FIR滤波器的单位冲激响应序列h(n)的各个参数值。 二、MATLAB软件仿真 利用matlab生成FIR低通滤波器的系数，并绘制器滤波器性能图。 FIR滤波器性能： 截止频率：50HZ 通带：50~100HZ FIR滤波器代码： ——————————————————————————————————————— fs = 1000; %采样频率 f = [50 100]; %通带 a = [1 0]; dev = [0.05 0.01]; [N,Wn,beta,ftype] = kaiserord(f,a,dev,fs); w = kaiser(N+1,beta); %wvtool(w) h = fir1(N,Wn,w); %滤波器系数 wvtool(h); [ha,w] = freqz(h,1024); plot(w/pi*400,abs(ha)); title(幅度谱); %添加标题 figure; plot(w,unwrap(angle(ha))); title(相位谱); %添加标题 ——————————————————————————————————————— 参数的FIR滤波器系数： h=[-0.0019,-0.0018,-0.0008,0.0010,0.0036,0.0062,0.0081,0.0082,0.0060,0.0011,-0.0061,-0.0142,-0.0212,-0.0249,-0.0230,-0.0137,0.0034,0.0276,0.0566,0.0871,0.1149,0.1362,0.1477,0.1477,0.1362,0.1149,0.0871,0.0566,0.0276,0.0034,-0.0137,-0.0230,-0.0249,-0.0212,-0.0142,-0.0061,0.0011,0.0060,0.0082,0.0081,0.0062,0.0036,0.0010,-0.0008,-0.0018,-0.0019]; FIR滤波器性能图： 在matlab上产生带有噪声的信号，经FIR滤波器滤波，对比滤波前后效果。 验证信号频率：20HZ 验证信号噪声：200HZ 验证FIR滤波器效果代码： ——————————————————————————————————————— clc; clear; %% SIN信号产生 fa=20; %信号频率 fz=200; %杂波频率 dt=0.001; t=0:dt:1; %采样频率fs=1/dt n1=length(t); x1=zeros(1,n1); x1=10000*(sin(2*pi*fa*t)+sin(2*pi*fz*t)); plot(t,x1); title(滤波前信号); %% FIR滤波 %h滤波器系数，截止频率50HZ，通带50~100HZ h=[-0.0019,-0.0018,-0.0008,0.0010,0.0036,0.0062,0.0081,0.0082,0.0060,0.0011,-0.0061,-0.0142,-0.0212,-0.0249,-0.0230,-0.0137,0.0034,0.0276,0.0566,0.0871,0.1149,0.1362,0.1477,0.1477,0.1362,0.1149,0.0871,0.0566,0.0276,0.0034,-0.0137,-0.0230,-0.0249,-0.0212,-0.0142,-0.0061,0.0011,0.0060,0.0082,0.0081,0.0062,0.0036,0.0010,-0.0008,-0.0018,-0.0019]; n2=length(h); x2=zeros(1,n2); x=zeros(1,n2+n1); x=[x2,x1]; %在信号前面插入n个0，便于计算 y=zeros(1,n1);%定义输出信号数组 for m=0:1000-n