exa070903_remez_2.m

生成一个正弦信号

%--------------------------------------------------------------------------
% exa070903_remez_2.m,   for example 7.9.3 and 7.4.2;
% to test remez.m and to design multi-band FIR filter;
%-------------------------------------------------------------------------
clear all;
clf;             %清屏
clear;           %清变量
w(1)=0.95;%0.95;
r(1)=0.80;
N=1024*2;          %设置采样数据的个数
for t=1:N        %计算产生系数w(t)和r(t)
    w(t+1)=0.99*w(t)+0.01;
    r(t+1)=0.99*r(t)+0.00995;
end

dt=1/8000;        %设置采样频率
tt=0:dt:dt*N;   %采样时间
%dis=2*(rand(size(tt)));          %产生随机噪声数据
%y=1000*sin(2*pi*1000*tt)+8*dis;   %产生加有噪声的正弦信号
y=wavread('single440Hz100db.wav');
y=y(:,1);
p0=10000/mean(y'*y);         %计算信号的均值
%p0=1000/mean(y);


% 用切比雪夫最佳一致逼近设计线性相位多带FIR滤波器；
f=[0 .14 .18 .22 .26 .34 .38 .42 .46 .54 .58 .62 .66 1];
A=[1 1  0 0 1 1 0 0 1 1 0 0 1 1];
weigh=[8 1 8 1 8 1 8];	
b=remez(128,f,A,weigh);
%
[h,w]=freqz(b,1,256,1);
hr=abs(h);
h=abs(h);
h=20*log10(h);
figure(1)
stem(b,'.');grid;
figure(2)
plot(w,h);grid;
qq=filter(w,h,y);
wvtool(y);
wvtool(qq);