MATLAB仿真信号试验题目，紧急求救

Question

有大神能做吗？

Answer 1

clc;
clear;
close all;

Am = 1;%调制幅度
fm = 50e3;%fm为50 kHz;
fs = 5e3;%载波信号频率5 kHz
As = 10;%载波幅度

f = 3*fm;%采样频率；
dt = 1/f;
%% 0秒到10ms秒情况，适合于0到1秒
time = 10e-3;%信号时间10ms
t1 = 0:dt:time-dt;%时间坐标(1ms一个区域）

ym_t1 = Am*sin(2*pi*fm*t1);%机械激振信号
Ks_t1 = As*sin(2*pi*fs*t1);%载波信号
delta_t1 = 1;%
y_t1 = ym_t1+Ks_t1.*delta_t1+ym_t1.*Ks_t1.*delta_t1;
n = length(y_t1);%信号的大小
yn_t = sqrt(0.1*max(y_t1.*conj(y_t1))*rand(1,n));%信噪比变为-10db的高斯白噪声 
y_t = y_t1+yn_t;

Y_ft = fftshift(fft(y_t))*dt/0.01;%傅里叶变换
fx = -f/2:1/time:f/2-1/time;%频域坐标


figure('Name','0s-0.1s信号及频谱','NumberTitle','off');
subplot(121);plot(t1,y_t);xlabel('time(s)');ylabel('Magnitude');
subplot(122);plot(fx,abs(Y_ft));xlabel('frequency(Hz)');ylabel('Magnitude');
%% 时频图参数
figure(2);
window = hamming(28);%使用默认海明窗口
noverlap = 10;%重叠长度
nfft = 1024;%采样点数
fss = 8000;%采样率
spectrogram(y_t,window,noverlap,nfft,fss,'yaxis');

%% 1秒到1.001s秒情况，适合于1到9秒
delta_t1 = 1;%
y_t1 = ym_t1+Ks_t1.*delta_t1+ym_t1.*Ks_t1.*delta_t1;
yn_t = sqrt(0.1*max(y_t1.*conj(y_t1))*rand(1,n));%信噪比变为-10db的高斯白噪声 
y_t = y_t1+yn_t;

Y_ft = fftshift(fft(y_t))*dt/0.01;%傅里叶变换
fx = -f/2:1/time:f/2-1/time;%频域坐标


figure('Name','1s-1.001s信号及频谱','NumberTitle','off');
subplot(121);plot(t1,y_t);xlabel('time(s)');ylabel('Magnitude');
subplot(122);plot(fx,abs(Y_ft));xlabel('frequency(Hz)');ylabel('Magnitude');
%% 时频图参数
figure(4);
window = hamming(128);%使用默认海明窗口
noverlap = 10;%重叠长度
nfft = 1024;%采样点数
fss = 8000;%采样率
spectrogram(y_t,window,noverlap,nfft,fss,'yaxis');

%% 9到10秒与1到2秒相同

我可太牛了