From 4f53b1ca67d67812acb2fd16f706b18b84f0b17a Mon Sep 17 00:00:00 2001
From: iridiumR <i@iridium.cyou>
Date: Thu, 5 May 2022 20:25:46 +0800
Subject: [PATCH] matlab

---
 Matlab/lab2.m     |   4 +-
 Matlab/lab2_ref.m | 130 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 131 insertions(+), 3 deletions(-)
 create mode 100644 Matlab/lab2_ref.m

diff --git a/Matlab/lab2.m b/Matlab/lab2.m
index 31ba27e..d19a878 100644
--- a/Matlab/lab2.m
+++ b/Matlab/lab2.m
@@ -1,7 +1,5 @@
 figure(1);
-Ts = 1/50;
-t = 0:Ts:10-Ts;                     
-x = sawtooth(t,0.5);
+sy
 plot(t,x)
 xlabel('Time (seconds)')
 ylabel('Amplitude')
diff --git a/Matlab/lab2_ref.m b/Matlab/lab2_ref.m
new file mode 100644
index 0000000..ad2cde5
--- /dev/null
+++ b/Matlab/lab2_ref.m
@@ -0,0 +1,130 @@
+figure(1);                 
+syms t n T;
+f1=4/T*t+1;
+f2=-4/T*t+1;
+a0=(int(f1,-T/2,0)+int(f2,0,T/2))/T;
+ya1=f1*cos(n*2*pi/T*t);
+ya2=f2*cos(n*2*pi/T*t); 
+yb1=f1*sin(n*2*pi/T*t);
+yb2=f2*sin(n*2*pi/T*t);
+an=(int(ya1,-T/2,0)+int(ya2,0,T/2))/T*2;
+bn=(int(yb1,-T/2,0)+int(yb2,0,T/2))/T*2;
+%1.2锯齿波信号频谱图
+cn=(an^2+bn^2)^(1/2);
+n=1:10;
+cn1=subs(cn);
+cn2=[0,cn1];
+h=stem([0,n],cn2);
+hold on;
+plot([0,n],cn2)
+title('幅度频谱')
+xlabel('\omega');
+ylabel('c_n');
+%相位当an大于0是相位为0，当an小于零的时候相位为pi
+
+
+figure(2);
+syms t w;
+ft=exp(-3*t)*heaviside(t);
+subplot(2,2,1);
+ezplot(ft);
+title('时域波形f(t)=e^-^3^tu(t)');
+xlabel('t');
+ylabel('f(t)');
+Fw=fourier(ft);
+w=-3:0.01:3;
+Fw1=subs(Fw);
+subplot(2,2,2);
+plot(w,abs(Fw1));   
+title('幅度谱');
+xlabel('角频率(\omega)'); 
+ylabel('幅度');
+subplot(2,2,3); 
+plot(w,angle(Fw1)*pi/180);
+title('相位谱');
+xlabel('角频率(\omega)'); 
+ylabel('相位\phi');
+
+
+figure(3);
+syms t w tao;
+tao=3;
+Fw=tao*sin(tao*w/2)/(tao*w/2);
+ft=ifourier(Fw,t);
+subplot(2,2,1);
+ezplot(ft,[-2,2]);
+title('时域波形f(t)');
+xlabel('t');
+ylabel('f(t)');
+subplot(2,2,2);
+ezplot(Fw,[-10,10]);
+title('频谱图');
+xlabel('\omega');
+subplot(2,2,3);
+ezplot(abs(Fw),[-10,10]);   
+title('幅度谱');
+xlabel('角频率(\omega)'); 
+ylabel('幅度');
+subplot(2,2,4);
+ezplot(angle(Fw),[-10,10]);
+title('相位谱');
+xlabel('\omega');
+ylabel('相位\phi');
+
+
+figure(4);
+syms w t;
+Fw=(1-j*w)/(1+j*w);
+w=-5:0.01:5;
+Fw1=subs(Fw);
+subplot(2,1,1);
+plot(w,abs(Fw1)); 
+title('幅度谱');
+xlabel('角频率(\omega)'); 
+ylabel('幅度|H(j\omega)|');
+subplot(2,1,2); 
+plot(w,angle(Fw1)*pi/180);
+xlabel('角频率(\omega)'); 
+ylabel('相位\phi');
+
+
+
+figure(5);
+syms w t;
+Hw=(1-j*w)/(1+j*w);
+ht=ifourier(Hw,t);    
+subplot(2,2,1);
+ezplot(ht);
+title('冲激响应');
+xlabel('t'); 
+ylabel('h(t)');
+ft=exp(-2*t)*heaviside(t);
+subplot(2,2,2); 
+ezplot(ft);
+title('输入信号f(t)=e^-^2^tu(t)');
+xlabel('t'); 
+ylabel('f(t)');grid on;
+Fw=fourier(ft);
+Yw=Fw*Hw;
+yt=ifourier(Yw,t);           
+subplot(2,2,3);
+ezplot(yt,[-1,4,-1,0.5]);
+title('零状态响应');
+xlabel('t'); 
+ylabel('y_f(t)');grid on;
+
+figure(6);
+ft=exp(-2*t)*heaviside(t);
+subplot(1,2,1); 
+ezplot(ft);
+title('e^-^2^tu(t)');
+xlabel('t'); 
+ylabel('f(t)');grid on;
+Fw=fourier(ft);
+Yw=Fw*Hw;
+yt=ifourier(Yw,t);           
+subplot(1,2,2);
+ezplot(yt,[-1,4,-1,0.5]);
+title('零状态响应');
+xlabel('t'); 
+ylabel('y_f(t)');