《DSP using MATLAB》示例Example5.7
代码：
x = [1, 1, 1, 1, zeros(1,4)];
N = 8; % zero-padding operation
X_DFT = dft(x,N); % DFT of x(n) magX_DFT = abs(X_DFT)
phaX_DFT = angle(X_DFT)*180/pi % degrees
realX_DFT = real(X_DFT); imagX_DFT = imag(X_DFT);
angX_DFT = angle(X_DFT); % radias n = 0:(N - 1);
k = 0:1000; w = (pi/500)*k; % [0,2pi] axis divided into 501 points.
%k = 0:500; w = (pi/500)*k; % [0,pi] axis divided into 501 points.
X_DTFT = x * (exp(-j*pi/500)) .^ (n'*k); % DTFT of x(n) magX_DTFT = abs(X_DTFT); angX_DTFT = angle(X_DTFT); realX_DTFT = real(X_DTFT); imagX_DTFT = imag(X_DTFT); figure('NumberTitle', 'off', 'Name', 'Exameple5.7 x sequence')
set(gcf,'Color','white');
stem(n,x); title('x sequence'); axis([0,N,-0.5,1.5]);
xlabel('n'); ylabel('x(n)'); grid on; %% --------------------------------------------------------------
%% START X_DTFT's mag ang real imag
%% --------------------------------------------------------------
figure('NumberTitle', 'off', 'Name', 'X_DTFT its Magnitude and Angle, Real and Imaginary Part');
set(gcf,'Color','white');
subplot(2,2,1); plot(w/pi,magX_DTFT); grid on; % axis([-2,2,0,15]);
title('Magnitude Part');
xlabel('frequency in \pi units'); ylabel('Magnitude |X\_DTFT|');
subplot(2,2,3); plot(w/pi, angX_DTFT*180/pi); grid on; % axis([-2,2,-1,1]);
title('Angle Part');
xlabel('frequency in \pi units'); ylabel('Degrees'); %axis([-200,200,0,2]); subplot('2,2,2'); plot(w/pi, realX_DTFT); grid on;
title('Real Part');
xlabel('frequency in \pi units'); ylabel('Real');
subplot('2,2,4'); plot(w/pi, imagX_DTFT); grid on;
title('Imaginary Part');
xlabel('frequency in \pi units'); ylabel('Imaginary');
%% --------------------------------------------------------------
%% END X_DTFT's mag ang real imag
%% -------------------------------------------------------------- %% --------------------------------------------------------------
%% START X_DFT's mag ang real imag
%% --------------------------------------------------------------
figure('NumberTitle', 'off', 'Name', 'Example5.7 X_DFT its Magnitude and Angle');
set(gcf,'Color','white');
subplot(2,1,1); stem(n,magX_DFT); hold on; plot(4*w/pi,magX_DTFT,'--'); hold off;
grid on; axis([-0.5,8.2,-1,5]);
title('Magnitude Part of the DFT: N = 8');
xlabel('k'); ylabel('Magnitude |X\_DFT|');
subplot(2,1,2); stem(n, phaX_DFT); hold on; plot(4*w/pi,angX_DTFT*180/pi,'--'); hold off;
grid on; axis([-0.5,8.2,-200,200]);
title('Angle Part of the DFT: N = 8');
xlabel('k'); ylabel('Degrees'); %axis([-200,200,0,2]); %subplot('2,2,2'); stem(n, realX_DFT); grid on;
%title('Real Part');
%xlabel('frequency in \pi units'); ylabel('Real');
%subplot('2,2,4'); stem(n, imagX_DFT); grid on;
%title('Imaginary Part');
%xlabel('frequency in \pi units'); ylabel('Imaginary');
%% --------------------------------------------------------------
%% END X_DFT's mag ang real imag
%% --------------------------------------------------------------
结果：
将序列末尾补12个零，长度达到16位
代码：
x = [1, 1, 1, 1, zeros(1,12)]; % append 12 zeros to the end of x(n)
N = 16; % zero-padding operation
X_DFT = dft(x,N); % DFT of x(n) magX_DFT = abs(X_DFT)
phaX_DFT = angle(X_DFT)*180/pi % degrees
realX_DFT = real(X_DFT); imagX_DFT = imag(X_DFT);
angX_DFT = angle(X_DFT); % radias n = 0:(N - 1);
k = 0:1000; w = (pi/500)*k; % [0,2pi] axis divided into 501 points.
%k = 0:500; w = (pi/500)*k; % [0,pi] axis divided into 501 points.
X_DTFT = x * (exp(-j*pi/500)) .^ (n'*k); % DTFT of x(n) magX_DTFT = abs(X_DTFT); angX_DTFT = angle(X_DTFT); realX_DTFT = real(X_DTFT); imagX_DTFT = imag(X_DTFT); figure('NumberTitle', 'off', 'Name', 'Exameple5.7 x sequence')
set(gcf,'Color','white');
stem(n,x); title('x sequence, N = 16'); axis([0,N,-0.5,1.5]);
xlabel('n'); ylabel('x(n)'); grid on; %% --------------------------------------------------------------
%% START X_DTFT's mag ang real imag
%% --------------------------------------------------------------
figure('NumberTitle', 'off', 'Name', 'X_DTFT its Magnitude and Angle, Real and Imaginary Part');
set(gcf,'Color','white');
subplot(2,2,1); plot(w/pi,magX_DTFT); grid on; % axis([-2,2,0,15]);
title('Magnitude Part');
xlabel('frequency in \pi units'); ylabel('Magnitude |X\_DTFT|');
subplot(2,2,3); plot(w/pi, angX_DTFT*180/pi); grid on; % axis([-2,2,-1,1]);
title('Angle Part');
xlabel('frequency in \pi units'); ylabel('Degrees'); %axis([-200,200,0,2]); subplot('2,2,2'); plot(w/pi, realX_DTFT); grid on;
title('Real Part');
xlabel('frequency in \pi units'); ylabel('Real');
subplot('2,2,4'); plot(w/pi, imagX_DTFT); grid on;
title('Imaginary Part');
xlabel('frequency in \pi units'); ylabel('Imaginary');
%% --------------------------------------------------------------
%% END X_DTFT's mag ang real imag
%% -------------------------------------------------------------- %% --------------------------------------------------------------
%% START X_DFT's mag ang real imag
%% --------------------------------------------------------------
figure('NumberTitle', 'off', 'Name', 'Example5.7 X_DFT its Magnitude and Angle');
set(gcf,'Color','white');
subplot(2,1,1); stem(n,magX_DFT); hold on; plot(8*w/pi,magX_DTFT,'--'); hold off;
grid on; axis([-0.5,16.2,-1,5]);
title('Magnitude Part of the DFT: N = 16');
xlabel('k'); ylabel('Magnitude |X\_DFT|');
subplot(2,1,2); stem(n, phaX_DFT); hold on; plot(8*w/pi,angX_DTFT*180/pi,'--'); hold off;
grid on; axis([-0.5,16.2,-200,200]);
title('Angle Part of the DFT: N = 16');
xlabel('k'); ylabel('Degrees'); %axis([-200,200,0,2]); %subplot('2,2,2'); stem(n, realX_DFT); grid on;
%title('Real Part');
%xlabel('frequency in \pi units'); ylabel('Real');
%subplot('2,2,4'); stem(n, imagX_DFT); grid on;
%title('Imaginary Part');
%xlabel('frequency in \pi units'); ylabel('Imaginary');
%% --------------------------------------------------------------
%% END X_DFT's mag ang real imag
%% --------------------------------------------------------------
结果：
继续补零，长度N=128，
代码：
x = [1, 1, 1, 1, zeros(1,124)]; % append 124 zeros to the end of x(n)
N = 128; % zero-padding operation
X_DFT = dft(x,N); % DFT of x(n) magX_DFT = abs(X_DFT)
phaX_DFT = angle(X_DFT)*180/pi % degrees
realX_DFT = real(X_DFT); imagX_DFT = imag(X_DFT);
angX_DFT = angle(X_DFT); % radias n = 0:(N - 1);
k = 0:1000; w = (pi/500)*k; % [0,2pi] axis divided into 501 points.
%k = 0:500; w = (pi/500)*k; % [0,pi] axis divided into 501 points.
X_DTFT = x * (exp(-j*pi/500)) .^ (n'*k); % DTFT of x(n) magX_DTFT = abs(X_DTFT); angX_DTFT = angle(X_DTFT); realX_DTFT = real(X_DTFT); imagX_DTFT = imag(X_DTFT); figure('NumberTitle', 'off', 'Name', 'Exameple5.7 x sequence')
set(gcf,'Color','white');
stem(n,x); title('x sequence, N = 128'); axis([0,N,-0.5,1.5]);
xlabel('n'); ylabel('x(n)'); grid on; %% --------------------------------------------------------------
%% START X_DTFT's mag ang real imag
%% --------------------------------------------------------------
figure('NumberTitle', 'off', 'Name', 'X_DTFT its Magnitude and Angle, Real and Imaginary Part');
set(gcf,'Color','white');
subplot(2,2,1); plot(w/pi,magX_DTFT); grid on; % axis([-2,2,0,15]);
title('Magnitude Part');
xlabel('frequency in \pi units'); ylabel('Magnitude |X\_DTFT|');
subplot(2,2,3); plot(w/pi, angX_DTFT*180/pi); grid on; % axis([-2,2,-1,1]);
title('Angle Part');
xlabel('frequency in \pi units'); ylabel('Degrees'); %axis([-200,200,0,2]); subplot('2,2,2'); plot(w/pi, realX_DTFT); grid on;
title('Real Part');
xlabel('frequency in \pi units'); ylabel('Real');
subplot('2,2,4'); plot(w/pi, imagX_DTFT); grid on;
title('Imaginary Part');
xlabel('frequency in \pi units'); ylabel('Imaginary');
%% --------------------------------------------------------------
%% END X_DTFT's mag ang real imag
%% -------------------------------------------------------------- %% --------------------------------------------------------------
%% START X_DFT's mag ang real imag
%% --------------------------------------------------------------
figure('NumberTitle', 'off', 'Name', 'Example5.7 X_DFT its Magnitude and Angle');
set(gcf,'Color','white');
subplot(2,1,1); stem(n,magX_DFT); hold on; plot(64*w/pi,magX_DTFT,'--'); hold off;
grid on; axis([-0.5,128.2,-1,5]);
title('Magnitude Part of the DFT: N = 128');
xlabel('k'); ylabel('Magnitude |X\_DFT|');
subplot(2,1,2); stem(n, phaX_DFT); hold on; plot(64*w/pi,angX_DTFT*180/pi,'--'); hold off;
grid on; axis([-0.5,128.2,-200,200]);
title('Angle Part of the DFT: N = 128');
xlabel('k'); ylabel('Degrees'); %axis([-200,200,0,2]); %subplot('2,2,2'); stem(n, realX_DFT); grid on;
%title('Real Part');
%xlabel('frequency in \pi units'); ylabel('Real');
%subplot('2,2,4'); stem(n, imagX_DFT); grid on;
%title('Imaginary Part');
%xlabel('frequency in \pi units'); ylabel('Imaginary');
%% --------------------------------------------------------------
%% END X_DFT's mag ang real imag
%% --------------------------------------------------------------
运行结果：
《DSP using MATLAB》示例Example5.7的更多相关文章
- DSP using MATLAB 示例Example3.21
代码: % Discrete-time Signal x1(n) % Ts = 0.0002; n = -25:1:25; nTs = n*Ts; Fs = 1/Ts; x = exp(-1000*a ...
- DSP using MATLAB 示例 Example3.19
代码: % Analog Signal Dt = 0.00005; t = -0.005:Dt:0.005; xa = exp(-1000*abs(t)); % Discrete-time Signa ...
- DSP using MATLAB示例Example3.18
代码: % Analog Signal Dt = 0.00005; t = -0.005:Dt:0.005; xa = exp(-1000*abs(t)); % Continuous-time Fou ...
- DSP using MATLAB 示例Example3.23
代码: % Discrete-time Signal x1(n) : Ts = 0.0002 Ts = 0.0002; n = -25:1:25; nTs = n*Ts; x1 = exp(-1000 ...
- DSP using MATLAB 示例Example3.22
代码: % Discrete-time Signal x2(n) Ts = 0.001; n = -5:1:5; nTs = n*Ts; Fs = 1/Ts; x = exp(-1000*abs(nT ...
- DSP using MATLAB 示例Example3.17
- DSP using MATLAB示例Example3.16
代码: b = [0.0181, 0.0543, 0.0543, 0.0181]; % filter coefficient array b a = [1.0000, -1.7600, 1.1829, ...
- DSP using MATLAB 示例 Example3.15
上代码: subplot(1,1,1); b = 1; a = [1, -0.8]; n = [0:100]; x = cos(0.05*pi*n); y = filter(b,a,x); figur ...
- DSP using MATLAB 示例 Example3.13
上代码: w = [0:1:500]*pi/500; % freqency between 0 and +pi, [0,pi] axis divided into 501 points. H = ex ...
- DSP using MATLAB 示例 Example3.12
用到的性质 代码: n = -5:10; x = sin(pi*n/2); k = -100:100; w = (pi/100)*k; % freqency between -pi and +pi , ...
随机推荐
- C#之数组篇
大杂烩 一.数组初始化 1.一维数组 String[] str = new String[3] { "1","2","3"}; ...
- Win7旗舰版-X86-X64-快速装机版
装机版作品简介 Win7 32/64位旗舰版 6.5z 专注于Win7,致力于做更好用的系统!一如既往的品质,不流氓,不欺骗,不夸大!一直在改进,只为做得更好!万千用户的信赖,作者的品质保证! 作品摘 ...
- 11月6日上午PHP练习《租房子》解析
一.题目要求 二.题目做法 1.建立数据库 2.封装类文件 <?php class DBDA { public $fuwuqi="localhost"; //服务器地址 pu ...
- 在Application中集成Microsoft Translator服务之使用http获取服务
一.创建项目 首先我们来创建一个ASP.NET Application 选择时尚时尚最时尚的MVC,为了使演示的Demo更简单,这里选择无身份验证 二.创建相关类 项目需要引入之前两个类AdmAcce ...
- Spring task定时任务
<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://mave ...
- Spring中配置和读取多个Properties文件--转
public class PropertiesFactoryBeanextends PropertiesLoaderSupportimplements FactoryBean, Initializin ...
- java运行过程
一.安装环境 大家在开发Java的时候,首先回装一个java的开发环境,一个JDK(也包含了JRE),然后设置环境变量,这个过程我就不细说了,大家装完后有没有发现,在装完这个环境的同时在安装JRE,在 ...
- bzoj1854 游戏
Description lxhgww最近迷上了一款游戏,在游戏里,他拥有很多的装备,每种装备都有2个属性,这些属性的值用[1,10000]之间的数表示.当他使用某种装备时,他只能使用该装备的某一个属性 ...
- avl树的操作证明
以下用大O表示节点,ABC表示三个集合. 仅分析左子树的情况,因为对称,右子树的情况一样. 插入节点前 O / \ O A / \ B C 插入节点后: O ...
- r-cnn学习（四）：train_faster_rcnn_alt_opt.py源码学习
论文看的云里雾里,希望通过阅读其代码来进一步了解. 参考:http://blog.csdn.net/sloanqin/article/details/51525692 首先是./tools/train ...