‫بسم هللا الرمحن الرحيم‬
Higher Technological Institute - Tenth of Ramadan City
Department of Electrical Engineering &computers
Subject : Digital control systems (EEC-161)
Time allowed: 1.5 Hrs
Examiner : Prof. Khalid M. Amin
Term: Summer 2019
Final term
-----------------------------------------------------------------------------------Answer all of the following questions
Q1.(15 marks)
a. Draw a complete block diagram for turbojet engine control system. The
system has one input "Pilot command" and one input "Aircraft state". At
each point of the system determine whether the signal is CT or DT?
b. For the following diff. equation, determine the order of the equation
and then test it for (i) linearity, (ii) time invariance, and (iii) homogeneity.
y(k+4) + sin(0.4k)y(k+1)+ 0.3y(k)=0
Q2. (10 marks)
a. For any LTI system, the following relation can be applied.
Define each term of the above relation? Calculate y(k) for h(k) = {00100} and
u(k)={1100}
Q3. (15 marks)
a. Solve the linear difference equation;
With all initial conditions equal zero.
b. Obtain (using partial fraction expansion) the inverse Z-transform of the
function
𝒁+𝟏
𝑭(𝒁) =
𝟎. 𝟎𝟐 + 𝟎. 𝟑 𝒁+𝒁𝟐
c. Use the delay property of Z-transform to find the transform of :
𝟒, 𝒌 = 𝟐, 𝟑, 𝟒, . .
𝒇(𝒌) = {
𝟎, 𝒐𝒕𝒉𝒆𝒓𝒘𝒊𝒔𝒆
‫وهللا ولي التوفيق‬
‫ خالد محمد أمين‬.‫د‬.‫ا‬,,
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