SSB(滤波法法)调制解调Matlab.m文件源码

%SSB信号调制解调

clear;clc;

f0 = 1; %信源信号频率(Hz)

E0 = 1; %信源信号振幅(V)

E = 1; %载波分量振幅(V)

fc = 10; %载波分量频率（Hz）

t0 = 1; %信号时长

snr = 15; %解调器输入信噪比dB

dt = 0.003; %系统时域采样间隔

fs = 1/dt; %系统采样频率

df = 0.001; %所需的频率分辨率

t = 0:dt:t0;

Lt = length(t); %仿真过程中，信号长度

snr_lin = 10^(snr/10);%解调器输入信噪比

%-------------画出调制信号波形及频谱

%产生模拟调制信号

m = E*cos(2*pi*f0*t);

L = min(abs(m));%包络最低点

R = max(abs(m));%包络最高点

%画出调制信号波形和频谱

clf;

figure(1);

%%

%画出调制信号波形

subplot(411);

plot(t,m(1:length(t)));

axis([0,t0,-R-0.3,R+0.3]);%设置坐标范围

xlabel('t');title('调制信号');

set(gca,'YTick',-R:1:R);

subplot(412);

[M,m,df1,f] = T2F_new(m,dt,df,fs); %求出调制信号频谱

[Bw_eq] = signalband(M,df,t0); %求出信号等效带宽

f_start_low = fc - Bw_eq; %求出产生下边带信号的带通滤波器的起始频率 f_cutoff_low = fc; %求出产生下边带信号的带通滤波器的截止频率 f_start_high = fc; %求出产生上边带信号的带通滤波器的起始频率 f_cutoff_high = fc + Bw_eq; %求出产生上边带信号的带通滤波器的截止频率

plot(f,fftshift(abs(M))); %画出调制信号频谱 %M：傅里叶变换后的频谱序列