[数字信号处理]IIR高通滤波器加速收敛算法实现

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clc;clear all;close all;

% 原信号
sample_rate = 100;
n           = 5000;
x           = 1:1:n;
data        = 50000 + 1000*sin((x/sample_rate)*2*pi);

% matlab 慢收敛方法高通滤波
[b,a] = butter(2,0.33/50,'high');
data_fil_matlab = filter(b,a,data);

% 加速收敛方法
y_buff  = zeros(1,3);x_buff  = zeros(1,3);
data_fil_accelerate = zeros(n,1);

for data_index = 1:1:n
     %滤波器
    if(data_index==1)
        x_buff(1) = data(data_index); 
        x_buff(2) = data(data_index);
        x_buff(3) = data(data_index);
    end
   
     %IIR HP*******************************************************************
	y_buff(1) = y_buff(2);y_buff(2) = y_buff(3);
	x_buff(1) = x_buff(2);x_buff(2) = x_buff(3);
   
    %赋值
	x_buff(3)  = data(data_index);
   
    y_buff(3) = (-1)*a(2)*y_buff(2)+(-1)*a(3)*y_buff(1)+...
					b(1)*x_buff(3)+b(2)*x_buff(2)+b(3)*x_buff(1);
   
    data_fil_accelerate(data_index) = y_buff(3);
end

figure(1);
subplot(3,1,1);
plot(data);
title('Original Data');grid on;
subplot(3,1,2);
plot(data_fil_matlab);
title('Matlab Method Data');grid on;
subplot(3,1,3);
plot(data_fil_accelerate);
title('Accelerate Method Data');grid on;