BACHELOR OF TECHNOLOGY IN ELECTRICAL AND ELECTRONICS ENGINEERING EET 3256: DIGITAL ELECTRONICS I CAT I DATE: 3RD JUNE, 2021 TIME: 60 MINUTES INSTRUCTIONS: Answer all questions (Total marks=30 marks) 1. With examples, differentiate between analog and digital quantities 2. a) Convert 0.5610 to binary, ending at 7 bits after the binary point b) Convert 2318 to a hexadecimal number c) Convert 5910 to Xs-3 code and state one advantage of the Xs-3 code 3. Simplify the following Boolean expression: (3 marks) (2 marks) (2 marks) (3 marks) (3 Marks) 4. Simplify the Boolean function 𝐹 (𝑤, 𝑥, 𝑦, 𝑧) = (1, 3, 7, 11, 15) which has the don’t-care conditions 𝑑 (𝑤, 𝑥, 𝑦, 𝑧) = (0, 2, 5) (4 marks) 5. Draw a waveform to represent the logic levels High(1) and Low (0) at output Y in Fig. Q(5a). Fig. Q(5b): shows the waveforms of the input A and B. (2 marks) (a) (b) Fig. Q(5) 6. Describe how to hardware-implement a four-input OR gate using two-input OR gates only. (3 Marks) 7. For the logic circuit shown in Fig. Q(7): i. Fig. Q(7) Determine the output (in terms of Boolean expressions) of all four logic gates in circuit (2 Marks) Page 1 of 2 ii. Complete a truth table for the circuit and from this derive the ‘sum of products’ expression. (3 Marks) 8. Suppose a design problem results in a minimized product of sums expression: 𝑥 = (𝐴 + 𝐵) (𝐵 + 𝐶) (𝐴 + 𝐶) Implement this expression using NOR gates only. (3 Marks)