【MATLAB】MATLAB 仿真模拟调制系统 — VSB 系统

目录

1、VSB 系统

2、程序运行结果

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1、VSB 系统

close all;
clear all;
clc;
fm = 5; %基带信号的最高频率
fc = 20; %载波中心频率
dt = 0.001; %时间采样间隔
T = 5; %信号时长
t = 0:dt:T;
mt = sqrt(2)*( cos(2*pi*fm*t) + sin(2*pi*0.1*fm*t) );
%VSB 调制
s_vsb = mt.*cos(2*pi*fc*t);
[f,sf] = T2F(t,s_vsb);
[t,s_vsb] = vsbpf(f,sf,0.2*fm,fm,fc);
figure;
subplot(3,1,1); plot(t,s_vsb,'b-');
hold on; plot(t,mt,'r:');
title('VSB 已调信号');
xlabel('t (s)'); grid on;
% VSB 已调信号的功率谱
[f,sf] = T2F(t,s_vsb);
psf = (abs(sf).^2)/T;
subplot(3,1,2); plot(f,psf,'b-');
axis([-2*fc, 2*fc, 0 max(psf)]);
title('VSB 信号功率谱');
xlabel('f (Hz)'); grid on;
%VSB 解调
rt = s_vsb.*cos(2*pi*fc*t);
% rt = rt-mean(rt);
[f,rf] = T2F(t,rt);
[t,rt] = lpf(f,rf,2*fm);
subplot(3,1,3); plot(t,rt,'b-');
hold on; plot