用Matlab软件画出下面两组信号的时域波形和频谱图，并简要说明信号特征。 用matlab绘出周期锯齿波信号的时域波形及频谱图，T=2p...
\u600e\u6837\u7528Matlab\u8f6f\u4ef6\u753b\u51fa\u4fe1\u53f7\u7684\u65f6\u57df\u6ce2\u5f62\u548c\u9891\u8c31\u56fet=0:0.001:1;
f1=sin(10*pi*t)+sin(100*pi*t)+sin(200*pi*t);
f2=sin(200*pi*t)+sin(10*pi*t)-sin(100*pi*t);
figure(1);
plot(t,f1,t,f2);
figure(2);
t=1000*(1:512)/1024;
ff1=fft(f1,1024)/1024;
dff1=2*abs(ff1(1:512));
ff2=fft(f2,1024)/1024;
dff2=2*abs(ff2(1:512));
plot(t,dff1,t,dff2);
\u9009\u91c7\u6837\u9891\u7387\u65f6\u6ce8\u610f\u91c7\u6837\u5b9a\u5f8b\u548c\u6ce2\u5f62\u7684\u5468\u671f\uff08\u91c7\u6837\u9891\u7387\u4e0d\u4f4e\u4e8e200hz\uff0c\u5468\u671f\u4e0d\u5c0f\u4e8e0.2s\uff09
%\u4ea7\u5cf0\u503c1\u4e09\u89d2\u6ce2\u6790\u51760~63\u8c10\u6ce2\u5e45\u503c\u8c31\u76f8\u4f4d\u8c31 clf; Fs =128; %\u91c7\u9891\u7387 T = 1/Fs; % \u91c7\u5468\u671f N = 128; % \u91c7\u70b9\u6570 t = (0:N-1)*T; % \u95f4\u5355\u4f4d\uff1aS x=zeros(N); for n=0:N-1 b=fix((n)/(N/4)); m=n+1; A=1/(N/4); if b==0 x(m)=A*n; elseif b==1||b==2 x(m)=A*(N/2-n); elseif b==3 x(m)=A*(n-N); end; end; n=0:N-1; subplot(3,1,1) plot(t,x); xlabel('\u95f4/S'); ylabel('\u632f\u5e45');title('\u57df\u6ce2\u5f62');grid on; y=fft(x,N); %\u4fe1\u53f7\u8fdb\u884c\u5feb\u901fFourier\u53d8\u6362 mag=abs(y)*2/N; %\u6c42\u53d6Fourier\u53d8\u6362\u632f\u5e45;*2/N\u8f6c\u53d8\u771f\u5b9e\u5e45\u503c f=n*Fs/N; subplot(3,1,2) plot(f(1:N/2),mag(1:N/2)); %\u7ed8Nyquist\u9891\u7387\u524d\u968f\u9891\u7387\u53d8\u5316\u632f\u5e45 xlabel('\u9891\u7387/Hz'); ylabel('\u632f\u5e45');title('\u5e45\u503c\u8c31');grid on; p=mod(angle(y)*180/pi,360); subplot(3,1,3) plot(f(1:N/2),p(1:N/2)); %\u7ed8Nyquist\u9891\u7387\u524d\u968f\u9891\u7387\u53d8\u5316\u76f8\u4f4d xlabel('\u9891\u7387/Hz'); ylabel('\u632f\u5e45');title('\u76f8\u4f4d\u8c31');grid on;
t=0:0.001:1;
f1=sin(10*pi*t)+sin(100*pi*t)+sin(200*pi*t);
f2=sin(200*pi*t)+sin(10*pi*t)-sin(100*pi*t);
figure(1);
plot(t,f1,t,f2);
figure(2);
t=1000*(1:512)/1024;
ff1=fft(f1,1024)/1024;
dff1=2*abs(ff1(1:512));
ff2=fft(f2,1024)/1024;
dff2=2*abs(ff2(1:512));
plot(t,dff1,t,dff2);
选采样频率时注意采样定律和波形的周期（采样频率不低于200Hz，周期不小于0.2s）
绛旓細f1,t,f2);figure(2);t=1000*(1:512)/1024;ff1=fft(f1,1024)/1024;dff1=2*abs(ff1(1:512));ff2=fft(f2,1024)/1024;dff2=2*abs(ff2(1:512));
绛旓細plot(x,y,x,y,'o')
绛旓細T=legend('1#','2#');set(T,'Fontsize',12); %璁剧疆鍥炬爣瀛椾綋澶у皬
绛旓細濡傛灉鏄竴涓晫闈袱寮犲浘 鐢 subplot锛1,2,1锛塸lot(x5,y);subplot(1,2,2)plot(x15,y);
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绛旓細t1 = 1:.01:6;y1 = t1.^2;t2 = 2:.01:10;y2 = 10*sin(t2);plot(t1,y1,'b-');hold onplot(t2,y2,'r-');hold offgrid on
绛旓細姹傛暀Matlab濡備綍灏嗗湪鍚屼竴涓浘閲鐢讳袱缁鏁版嵁鐨勭洿鏂瑰浘 鐢诲畬涓涓,杈撳叆hold on,]鐒跺悗鍐鐢讳笅涓浘,杩欎袱涓浘灏卞湪涓璧蜂簡
绛旓細鏃堕棿蹇呴』瑕佹敼鎴愭暟鍊肩殑鎵嶈兘鐢伙紝浣嗘槸鍧愭爣杞翠笂鍙互鏍囨垚杩欐牱銆倄1=[1,3,5];y1=[1,2,3]x2=[1,2,4];y2=[2,4,7];figure;hold on;plot(x1,y1,'b-o');plot(x2,y2,'r-o');set(gca,'Xtick',1:5,'XtickLabel',{'00:01','00:02','00:03','00:04','00:05'});legend('...
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