求matlab大神解答仿真问题

Roof0102

如何用matlab仿真一个正弦+余弦+随机信号的频谱图

killer00

weqwewqeqwew

Blah

建议在帮助中搜fft，其范例example就是很好的例子，直接看英文原文更详细。程序如下，
%%模拟创建需要观察的信号
6 `! x+ Y! v. s- m6 a& |Fs = 1000; % Sampling frequency
T = 1/Fs; % Sample time
L = 1000; % Length of signal
t = (0P-1)*T; % Time vector
- P; t3 T4 f8 M( _* s% Sum of a 50 Hz sinusoid and a 120 Hz sinusoid
& D4 k( F5 j: ^3 S8 Cx = 0.7*sin(2*pi*50*t) + sin(2*pi*120*t);
%这里改成加个cos的就是你想要的了 幅度相位平率组合自己设置吧
: n0 c4 u! b' |7 g) w- iy = x + 2*randn(size(t)); % Sinusoids plus noise
0 e4 W1 @; W' w1 F# splot(Fs*t(1:50),y(1:50))
) `" ^& ?  D& ?& r1 g( x% Z, S1 ^title('Signal Corrupted with Zero-Mean Random Noise')
1 z6 n3 F+ Z, Cxlabel('time (milliseconds)')
%%fft观察信号的频谱图
NFFT = 2^nextpow2(L); % Next power of 2 from length of y
* N! q1 _% R) t3 ]  l: PY = fft(y,NFFT)/L;
f = Fs/2*linspace(0,1,NFFT/2+1);
5 s( {0 b3 {0 K" v* K% Plot single-sided amplitude spectrum.
plot(f,2*abs(Y(1:NFFT/2+1)))
title('Single-Sided Amplitude Spectrum of y(t)')
% x, \: x% y) f2 w1 axlabel('Frequency (Hz)')
ylabel('|Y(f)|')

oponi

楼上说的很不错

ESCAPE

再看看别人是怎么说的