《DSP using MATLAB》Problem 5.28

昨晚手机在看X信的时候突然黑屏，开机重启都没反应，今天维修师傅说使用时间太长了，还是买个新的吧，心疼银子啊！

这里只放前两个小题的图。

代码：

1、

%% +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

%%            Output Info about this m-file

fprintf('\n***********************************************************\n');

fprintf('        <DSP using MATLAB> Problem 5.28 \n\n');

banner();

%% +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

% -------------------------------------------------------------------

%       Computer N-point Circular Convolution

% -------------------------------------------------------------------

n1 = [0:5];

x1 = sin(pi*n1/3);

N1 = length(x1);

n2 = [0:7];

x2 = cos(pi*n2/4);

N2 = length(x2);

% --------------------------------------------

%        1st way TIME domain

% --------------------------------------------

N = 10;

n = [0:N-1];

y1 = circonvt(x1, x2, N);

% --------------------------------------------

%   2nd way ----  circular conv(FREQ domain)

% --------------------------------------------

y2 = circonvf(x1, x2, N);

% --------------------------------------------

%   3rd way --- Cir Conv (Circulant Matrix)

% --------------------------------------------

y3 = circonvt_v3(x1, x2, N);

figure('NumberTitle', 'off', 'Name', 'P5.28.1 x1(n) and x2(n)')

set(gcf,'Color','white');

subplot(2,1,1); stem(n1, x1);

xlabel('n'); ylabel('x1(n)');

title('x1(n), N=6');  grid on;

subplot(2,1,2); stem(n2, x2);

%axis([-N/2, N/2, -0.5, 50.5]);

xlabel('n'); ylabel('x2(n)');

title('x2(n), N=8');  grid on;

figure('NumberTitle', 'off', 'Name', 'P5.28.1 Cir-Conv, N=10')

set(gcf,'Color','white');

subplot(3,1,1); stem(n, y1);

xlabel('n'); ylabel('y1(n)');

title('Time Domain, y1(n)');  grid on;

subplot(3,1,2); stem(n, y2);

%axis([-N/2, N/2, -0.5, 50.5]);

xlabel('n'); ylabel('y2(n)');

title('FREQ domain, y2(n)');  grid on;

subplot(3,1,3); stem(n, y3);

%axis([-N/2, N/2, -0.5, 50.5]);

xlabel('n'); ylabel('y3(n)');

title('Circulant Matrix, y3(n)');  grid on;

　　运行结果：

计算圆周卷积的两序列

三种方法计算圆周卷积

2、

代码：

%% +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

%%            Output Info about this m-file

fprintf('\n***********************************************************\n');

fprintf('        <DSP using MATLAB> Problem 5.28 \n\n');

banner();

%% +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

% -------------------------------------------------------------------

%       Computer N-point Circular Convolution

% -------------------------------------------------------------------

N = 32;

n1 = [0:N-1];

x1 = cos(2*pi*n1/N);

N1 = length(x1);

n2 = [0:N-1];

x2 = sin(2*pi*n2/N);

N2 = length(x2);

% --------------------------------------------

%        1st way TIME domain

% --------------------------------------------

%N = 10;

n = [0:N-1];

y1 = circonvt(x1, x2, N);

% --------------------------------------------

%   2nd way ----  circular conv(FREQ domain)

% --------------------------------------------

y2 = circonvf(x1, x2, N);

% --------------------------------------------

%   3rd way --- Cir Conv (Circulant Matrix)

% --------------------------------------------

y3 = circonvt_v3(x1, x2, N);

figure('NumberTitle', 'off', 'Name', 'P5.28.2 x1(n) and x2(n)')

set(gcf,'Color','white');

subplot(2,1,1); stem(n1, x1);

xlabel('n'); ylabel('x1(n)');

title('x1(n)=cos(2*pi*n1/N), N=32');  grid on;

subplot(2,1,2); stem(n2, x2);

%axis([-N/2, N/2, -0.5, 50.5]);

xlabel('n'); ylabel('x2(n)');

title('x2(n)=sin(2*pi*n2/N), N=32');  grid on;

figure('NumberTitle', 'off', 'Name', 'P5.28.2 Cir-Conv, N=32')

set(gcf,'Color','white');

subplot(3,1,1); stem(n, y1);

xlabel('n'); ylabel('y1(n)');

title('Time Domain, y1(n)');  grid on;

subplot(3,1,2); stem(n, y2);

%axis([-N/2, N/2, -0.5, 50.5]);

xlabel('n'); ylabel('y2(n)');

title('FREQ domain, y2(n)');  grid on;

subplot(3,1,3); stem(n, y3);

%axis([-N/2, N/2, -0.5, 50.5]);

xlabel('n'); ylabel('y3(n)');

title('Circulant Matrix, y3(n)');  grid on;

　　运行结果：

代码结构都一样

圆周卷积结果