From a17a2e0ff18f5c0094443e1449eb1b078872e077 Mon Sep 17 00:00:00 2001
From: iridiumR <i@iridium.cyou>
Date: Sat, 28 May 2022 00:35:34 +0800
Subject: [PATCH] Matlab

---
 Matlab/lab4.m | 74 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 74 insertions(+)
 create mode 100644 Matlab/lab4.m

diff --git a/Matlab/lab4.m b/Matlab/lab4.m
new file mode 100644
index 0000000..cf0a334
--- /dev/null
+++ b/Matlab/lab4.m
@@ -0,0 +1,74 @@
+%% 1
+a = [1, -1, 0, 0.9];
+b = 1;
+subplot(3,1,1);
+impz(b,a);
+subplot(3,1,2);
+impz(b,a,60);
+subplot(3,1,3);
+impz(b,a,-10:40);
+y = impz(b,a,-5:10);
+display(y);
+
+%% 2
+a = [1, 0.4, -0.12];
+b = [1, 2];
+k = 0:10;
+y=dstep(b,a,11);
+stem(k,y);
+display(y);
+
+%% 3-1
+syms n;
+f = sym('1');
+Z1 = ztrans(f);
+display(Z1);
+
+%% 3-2
+syms a;
+syms n;
+f2 = a^n; 
+Z2 = ztrans(f2);
+display(Z2);
+
+%% 3-3
+f3 = 0.5*n*(heaviside(n)-heaviside(n-5));
+Z3 = ztrans(f3);
+display(Z3);
+
+%% 3-4
+f4 = a^n*cos(n*pi/2)*heaviside(n);
+Z4 = ztrans(f4);
+display(f4);
+display(Z4);
+
+%% 4-1
+syms n z;
+f = (-1)^n*heaviside(n);
+h = (-1)^n/3+2*3^n/3*heaviside(n);
+F = ztrans(f);
+H = ztrans(h);
+Y = H*F;
+y = iztrans(Y);
+display(y);
+
+%% 4-2
+syms n z;
+H = z*(7*z-2)/((z-0.2)*(z-0.5));
+f = 1^n;
+F = ztrans(f);
+Y = F*H;
+y = iztrans(Y);
+display(y);
+
+%% 5
+a= [1 2^(1/2) 1];
+b = [1 0 0];
+subplot(2,1,1);
+impz(b,a,-2:20);
+display(impz(b,a,-2:20));
+subplot(2,1,2);
+p = roots(a);
+z = roots(b);
+zplane(z,p);
+