Adaptive Filters and Applications - Digital Signal Processing: Fundamentals and Applications - page 471

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FIGURE 10.13

The waveforms for the unknown system's output, adaptive filter output, and error output.

% Bandpass filter design
% for the assumed unknown system using the bilinear transformation
%(BLT) method (see Chapter 8)
wd1 ¼ 1400*2*pi; wd2 ¼ 1600*2*pi;

wa1 ¼ (2/T)*tan(wd1*T/2); wa2 ¼ (2/T)*tan(wd2*T/2);

BW wa2-wa1;

w0 ¼ sqrt(wa2*wa1);
[B,A] ¼ lp2bp([1],[1 1.4141 1],w0,BW);
[b,a] ¼ bilinear(B,A,fs);
freqz(b,a,512,fs); axis([0 fs/2 -80 1]); % Frequency response plots
figure
t ¼ 0:T:0.1; % Generate the time vector
x ¼ cos(2*pi*500*t) þ sin(2*pi*1500*t) þ cos(2*pi*2500*t þ pi/4);
d ¼ filter(b,a,x); % Produce unknown system output
mu ¼ 0.01; % Convergence factor
w ¼ zeros(1,21); y ¼ zeros(1,length(t)); % Initialize the coefficients and output
e ¼ y; % Initialize the error vector
% Perform adaptive filtering using LMS algorithm
for m ¼ 22:1:length(t)-1
sum ¼ 0;
for i ¼ 1:1:21

¼