Vestigal side band matlab code

31 次查看（过去 30 天）
ong jia eek
ong jia eek 2019-10-19
回答： MD Rasel Basunia 2022-4-8
%>>>>>>>>>>>>>>>>>>>> Tuterial on AM vestigial sideband Modulation <<<<<<<<<<<<<<<<<<<<<<<<<<
clc;
close all;
clear all;
%XXXXXXXXXXXXXXXXXXXXXXXXXXX Define AM modulation Index XXXXXXXXXXXXXXXXXXX
disp(' example: m=1 means 100% modulation');
m=input(' Enter the value of modulation index (m) = ');
%m=1; % for 100% modulation
if (0>m||m>1)
error('m may be less than or equal to one and greater0 than to zero');
end
%XXXXXXXXXXXXXXXXX modulating signal generation XXXXXXXXXXXXXXXXXXXXXXXXXX
Am =input('Enter the value of amplitude modulation =');
n=input('Enter number of cycles = '); % input for number of modulationd signal cycles
%Am=5; % Amplitude of modulating signal
fa=2000; % Frequency of modulating signal
Ta=1/fa; % Time period of modulating signal
t=0:Ta/999:n*Ta; % Total time for simulation
ym=Am*sin(2*pi*fa*t); % Equation of modulating signal
figure(1)
subplot(3,1,1);
plot(t,ym), grid on;% Graphical representation of Modulating signal
%axis ([0 1 -5 5]);
title ( ' Modulating Signal ');
xlabel ( ' time(sec) ');
ylabel (' Amplitud(volt) ');
%XXXXXXXXXXXXXXXXXXXXX carrier signal generation XXXXXXXXXXXXXXXXXXXXXXXXXX
Ac=Am/m;% Amplitude of carrier signal [ where, modulation Index (m)=Am/Ac ]
fc=fa*10;% Frequency of carrier signal
Tc=1/fc;% Time period of carrier signal
yc=Ac*sin(2*pi*fc*t);% Eqation of carrier signal
subplot(3,1,2);
plot(t,yc), grid on;% Graphical representation of carrier signal
title ( ' Carrier Signal ');
xlabel ( ' time(sec) ');
ylabel (' Amplitud(volt) ');
%XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX AM Modulation XXXXXXXXXXXXXXXXXXXXXXXXXXXXX
y=Ac*(1+m*sin(2*pi*fa*t)).*sin(2*pi*fc*t)(; % Equation of Amplitude
%modulated signal
subplot(3,1,3);
plot(t,y);% Graphical representation of AM signal
title ( ' Amplitude Modulated signal ');
xlabel ( ' time(sec) ');
ylabel (' Amplitud(volt) ');
grid on;
%>>>>>>>>>>>>>>>>>>>>>> end of program <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
How to change this matlab code to vestigial side band?
How can we put frequency code here?
  1 个评论
dhanvanth voona
dhanvanth voona 2021-5-21
this is only amplitude modulation, we need to design appropriate filters and apply them to message signals to obtain VSB

请先登录，再进行评论。

请先登录，再回答此问题。

回答（1 个）

MD Rasel Basunia
MD Rasel Basunia 2022-4-8
%% message signal m(t)=u(t+2)-u(t-2)
syms t f
fc=10;%let carrier frequency frequency contain 10 Hz .x_carrier=cos(2*pi*10*t)
x = heaviside(t+2)- heaviside(t-2) %% Fourier transform of m(t)
X=fourier(x,f) ;% fourier transform
%% using anonymous function
XX = @(f) 2*(sin(2*f)./(f))
f=[-100:0.01:100-0.01];% proper frequency range .Avoiding 0 / 0.
%% Generation of DSB-SC
Xshift=( XX(f-fc)+XX(f+fc));
%% Designing VSB shaping filter characteristic
% Define normalized VSB shaping filter
Hf = @(f) ((f>=9 & f<=20)) ;
%% Generating SSB
SSB =@(f) Xshift.*(f>=10 & f<=50) + Xshift.*(f<=-10 & f>=-50);
%%Here I am just plotting SSB-SC and VSB modulation signals.you can also
%%plot Hf(f) characteristic normalized filter and DSB-SC from equation.
%% Generation of VSB
VSB_upper = @(f)((XX(f-fm)+XX(f+fm)).*Hf(f)) %SSB(f).*Hf(f)SB_upper = @(f)((XX(f-fm)+XX(f+fm)).*Hf(f)) %SSB(f).*Hf(f)
subplot(211)
%% ploting SSB
plot(f,abs(SSB(f)),[-10,-10],[0,4],[10 10],[0,4],'r','linewidth',1.5);
% set axis for visualize porpuse only
xlim([-35 35]);
grid on;ylim([0 6]);xlabel('frequency in Hz');ylabel('Magnitude spectrum');
legend('| SSB-SC|');
title('Single Sideband Modulation');
%% ploting VSB
subplot(212)
plot(f,abs(VSB_upper(f)),'b',-f,abs(VSB_upper(f)),'k','linewidth',1.5);grid on;
xlabel('frequency in Hz');ylabel('Magnitude spectrum');
title('SSB');ylim([0 6]);legend('| VSB |');
% set axis for visualize purpose
xlim([-35 35]);
% see carefully around 10 Hz .A vestige was found before +10 Hz and also in
% case negative -10 Hz

类别

在 Help Center 和 File Exchange 中查找有关 MATLAB 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by