= = TAαn = 0:50； % defines the length of the sequence as 50a =1; % Set the signal related parameter A = 0.4t =1; % sampling rate w0 = 2.0734x=A*exp(-a*n*T). * sin(w0 * n * T)； %pi is π defined by MATLAB, and signal multiplication can be used. *" closeall% clears the subdivision of the drawn x(n) graph (3, 1,1); Stem (x); % draw graphic title ('of x(n)'); k =-25:25； w =(pi/ 12.5)* k； X=x*(exp(-j*pi/ 12.5))。 ^(n'*k)； magX = ABS(X)； % Plot the amplitude spectrum of x(n) (3, 1, 2); Stem (magx); Title ("amplitude spectrum of ideal sampling signal sequence"); AngX = angle (x); % Plot the phase spectrum of x(n) (3, 1, 3); stem(angX)； Title ("Phase Spectrum of Ideal Sampling Signal Sequence") 2. Unit pulse sequence in MatLab, this function can be realized by zero function: n =1:50; The length of% defined sequence is 50x = zero (1, 50); % Note: array subscripts in MATLAB start from 1, and x (1) =1; All closed; Subplots (3, 1,1); Stem (x); Title ('unit shock signal sequence'); k =-25:25； X=x*(exp(-j*pi/ 12.5))。 ^(n'*k)； magX = ABS(X)； % Plot the amplitude spectrum of x(n) (3, 1, 2); Stem (magx); Title ("Amplitude Spectrum of Unit Shock Signal"); AngX = angle (x); % Plot the phase spectrum of x(n) (3, 1, 3); stem(angX)； Title ('phase spectrum of unit shock signal') 3. Rectangular sequence n =1:50x = sign (sign (10-n)+1); All closed; Subplots (3, 1,1); Stem (x); Title ('unit shock signal sequence'); k =-25:25； X=x*(exp(-j*pi/25))。 ^(n'*k)； magX = ABS(X)； % Plot the amplitude spectrum of x(n) (3, 1, 2); Stem (magx); Title ("Amplitude Spectrum of Unit Shock Signal"); AngX = angle (x); % Plot the phase spectrum of x(n) (3, 1, 3); stem(angX)； Title ("Phase Spectrum of Unit Impulse Signal") 4. Specific earthquake series:) 3()2(5.2) 1(5.2) (? +? +? += nnnnnxδδδn = 1:50； The length of% defined sequence is 50x = zero (1, 50); % Note: array subscripts in MATLAB start from 1, and x (1) =1; x(2)= 2.5； x(3)= 2.5； x(4)= 1； All closed; Subplots (3, 1,1); Stem (x); Title ('unit shock signal sequence'); k =-25:25； X=x*(exp(-j*pi/ 12.5))。 ^(n'*k)； magX = ABS(X)； % Plot the amplitude spectrum of x(n) (3, 1, 2); Stem (magx); Title ("Amplitude Spectrum of Unit Shock Signal"); AngX = angle (x); % Plot the phase spectrum of x(n) (3, 1, 3); stem(angX)； Title ("Phase Spectrum of Unit Impulse Signal") 5. Convolution calculation: ∑ +∞? ∞= ? =? = mmmnhmxnhnxny) () () () () (in MATLAB. Conv (y=conv(x, h)) is provided, which is very convenient to call. For example: system:) 3()2(5.2) 1(5.2) (? +? +? += nnnnnh b δδδδ signal: 500)，sin () (0