UNIVERSITY OF BOLTON TW5 SCHOOL OF ENGINEERING BENG (HONS) ELECTRICAL AND ELECTRONIC ENGINEERING SEMESTER EXAMINATION 6/7 ANALOGUE SIGNAL PROCESSING & COMMUNICATION MODULE NO: EEE55 Date: Friday 9 May 7 Time:. 4. INSTRUCTIONS TO CANDIDATES: There are 6 questions. Answer 4 questions. All questions carry equal marks. Marks for parts of questions are shown in brackets. This examination paper carries a total of marks. All working must be shown. A numerical solution to a question obtained by programming an electronic calculator will not be accepted.
Page of 7 Q a) What is meant by the half power point in relation to filters. [5 marks] b) If a voltage of Vrms is input to a system and the output produced is.vrms. What is the gain of the system in db? [5 marks] c) A passive low pass filter can be constructed from a single resistor and capacitor. i) Draw the circuit diagram for a passive Low Pass filter and derive an equation for the gain v out v in.. [5 marks] ii) iii) Design the filter to have a cut-off frequency of Hz. The Resistor should have a value between Ohms and Ohms. [5 marks] Calculate the gain at appropriate frequencies and hence plot the bode diagram (magnitude only) for the circuit. [5 marks] Q a) Sketch the following signals. f(t) = u(t ) f(t) = e t f(t) = sin (πt π) f(t) = u(t ) u(t 4) [8 marks] b) If f(t) = 4t +, and a =, sketch the following signals i) g(t) = f(t)u(t) ii) g(t) = f(t)u(t-a) iiii) g(t) = f(t-a)u(t) [6 marks]
Page of 7 Question continued Question continued over the page c) A signal is described by the expression f(t) = (-t + 4) * ( u(t - ) u(t - ) ) i) Sketch this signal [5 marks] ii) Sketch the signal g(t) = f(-t) [6 marks] Q a) Using the properties of convolution simplify the following system shown in Fig Qa. [5 marks] Figure Qa b) The diagrams Figure Qb, and Qc each show an input x(t) to a system which is defined by its impulse response h(t). Sketch the output in each case. ( marks) Figure Qb
Page 4 of 7 Question continued over the page Question continued Figure Qc c) Using the convolution integral derive expressions for y(t) from the signals x(t), and h(t) given below: [ marks] x(t) = u(t) u(t ) and h(t) = u(t) u(t ) Q4 a) Explain what is meant by a transfer function s poles and zeros. What constraints need to be placed on the transfer function to ensure that the network is realizable? (7 marks) b) Evaluate each of the poles and zeros defined by the transfer function: (8 marks)
Page 5 of 7 Question 4 continued over the page Question 4 continued c) Sketch the impulse response of the systems defined by the s-domain pole/zero plots shown in figure Q4a, Q4b, and Q4c. ( marks) - - - - - - Q4a Q4b Q4c Please turn the page
Page 6 of 7 Q5 a) Sketch the frequency response of the systems defined by the pole/zero configurations shown in Figure Q5a and Q5b. [ marks] - - - Figure Q5a - Figure Q5b b) Use graphical or trigonometrical techniques to evaluate the magnitude and phase response of the system defined by Figure Qa at a frequency of rad/s. ( marks) Q6 a) Briefly describe the term modulation and explain why it is useful for broadcasting signals. [ marks] b) Describe the three basic types of modulation. [5 marks] c) Describe the term Muliplexing and illustrate two methods that can be used to achieve it. [ marks]
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