1. What does the Karnaugh map (K-map) help to achieve in Boolean expressions?

A. Convert expressions from binary to decimal B. Simplify Boolean expressions C. Generate truth tables D. Maximize the number of logic gates used

2. How many output voltage steps will a 6-bit D/A converter have?

A. 32 B. 64 C. 128 D. 256

3. The POS form expression f = π M(0,1,2,3,4,5) implies what about the corresponding SOP form?

A. It contains minterms 0 to 5 only B. It contains minterms 6 and 7 only C. It contains minterms 6 and 7 and excludes 0 to 5 D. It is invalid

4. The binary multiplication of two bits A and B follows which rule?

A. 0 x 0 = 1 B. 1 x 0 = 1 C. 1 x 1 = 1 D. 0 x 1 = 1

5. What error is introduced when the output of a DAC does not exactly match the original analog input after A/D and D/A conversion?

A. Gain error B. Offset error C. Quantization error D. Setting time error

6. What is the outcome when performing BCD addition that results in an illegal code (greater than 9)?

A. Add 0110 (6) to the sum and carry over 1 B. Subtract 0110 (6) from the sum C. Ignore the carry D. Restart the addition process

7. How can an OR gate be realized using only NOR gates?

A. By inverting the NOR gate output twice B. Connecting inputs directly to the NOR gate C. Using additional AND gates D. It cannot be realized using NOR gates

8. Which gate's output is represented by the Boolean expression A XNOR B?

A. NAND B. XOR C. XNOR D. NOR

9. Which of the following best describes a full adder circuit?

A. A circuit that adds two binary digits without carry input B. A sequential circuit that stores binary numbers C. A combinational circuit that adds three bits to produce a sum and carry D. A network of logic gates used to subtract binary numbers

10. How does BCD subtraction handle borrow occurrences during digit subtraction?

A. Adds 0110 to the difference term B. Subtracts 0110 from the difference term where borrow occurred C. Ignores the borrow D. Converts to decimal and subtracts normally

11. Which gates are considered universal gates?

A. AND and OR B. NAND and NOR C. XOR and XNOR D. NOT and AND

12. What is a universal gate in digital logic design?

A. A gate that can only perform AND and OR operations B. A gate that can be configured to perform any basic logic function C. A gate that only outputs high signals D. A gate used exclusively for arithmetic operations

13. Which Boolean law allows the simplification A(B + C) = AB + AC?

A. Distributive Law 1 B. Distributive Law 2 C. Associative Law D. Commutative Law

14. Which of the following laws states that A + AB = A + B?

A. Distributive Law B. Redundant Literal Rule C. De Morgan’s Law D. Consensus Theorem

15. How is the accuracy of a D/A converter typically expressed?

A. As an absolute voltage difference B. As the time taken to settle at a new output voltage C. As a percentage of the maximum output voltage D. As the number of output steps

16. How many discrete voltage steps are there in a 6-bit ADC?

A. 32 B. 64 C. 128 D. 256

17. Which code is known as a self-complementing, non-weighted BCD code?

A. Gray code B. Excess-3 code C. ASCII code D. Binary code

18. What is the Boolean expression for a NAND gate output with inputs A and B?

A. A + B B. AB C. (AB)' D. A'B'

19. In a binary ladder network for a DAC, what resistor values are used?

A. Multiple values including one-eighth of the largest resistor B. Only two resistance values C. Only one resistor value D. Random resistor values are used to minimize error

20. Quantization error can be expressed as:

A. ±1 LSB B. ±1/2 the maximum input voltage C. ±1/2 LSB D. ±1 LSB squared

21. In a 4-bit digital-to-analog converter (DAC) using a weighted register network, what is the ratio of the MSB resistor to the LSB resistor?

A. 8 times larger B. Equal resistance C. One-eighth of the LSB resistance D. Two times the LSB resistance

22. In Gray code conversion, what is a key property that makes it useful?

A. Each successive code differs by only one bit B. It is identical to binary code C. It requires no conversion to decimal D. It is easier to perform addition directly

23. For a four-variable K-map, how many cells does it contain?

A. 4 B. 8 C. 12 D. 16

24. What is meant by the "setting time" of a D/A converter?

A. Time taken for the input digital signal to change B. Time taken for the output voltage to settle within ±1/2 LSB of its final value C. Time taken for the conversion from analog to digital D. Time delay introduced by the resistor network

25. What is the binary equivalent of Gray code 1101 according to the example?

A. 1101 B. 1001 C. 1011 D. 1110

26. In the process of minimizing Boolean expressions using a Karnaugh Map (K-map), what is the significance of grouping minterms into pairs, quads, or octets?

A. To increase the number of logic gates required B. To create larger expressions for complexity C. To simplify the Boolean expression by combining adjacent ones D. To separate independent variables

27. What is the logic expression for output Q of a NOR gate with inputs A and B?

A. A + B B. AB C. (A + B)' D. (AB)'

28. What is the function of a JK flip flop converted into a D flip flop?

A. It removes race conditions B. It makes flip flop inputs dependent only on the D input and current output C. It allows asynchronous operation D. It confirms outputs change on clock falling edge

29. How many minterms are represented in a four-variable SOP expression represented on a K-map?

A. 2^4 = 8 B. 2^4 = 16 C. 4 D. 8

30. How can you realize an AND gate using only NAND gates?

A. Connect outputs of multiple NAND gates to an OR gate B. Connect inputs directly to a NAND gate C. Connect the output of a NAND gate to another NAND gate acting as an inverter D. Connect inputs through NOT gates to a NAND gate

31. What is the primary cause of quantization error in an analog-to-digital converter (ADC)?

A. Variations in input voltage range B. Limited discrete output levels corresponding to continuous input values C. Noise in the converter circuitry D. Clock timing errors

32. Which is a key property of distributive laws in Boolean algebra?

A. They allow expansion or factoring of Boolean expressions B. They eliminate variables C. They convert binary to Gray code D. They generate truth tables

33. What is the main purpose of De Morgan’s theorem in Boolean algebra?

A. To add variables B. To convert between AND/OR forms C. To define the distributive law D. To simplify timing diagrams

34. Which of the following best describes the purpose of a Karnaugh Map (K-Map) in digital logic design?

A. It converts hexadecimal numbers into binary equivalents. B. It diagrams the internal structure of flip-flops for timing analysis. C. It provides a systematic method to simplify Boolean expressions by grouping minterms or maxterms. D. It determines the speed at which an analog-to-digital converter completes its conversions.

35. Why is monotonicity an important characteristic in D/A converters?

A. It ensures the output never decreases when the input increases B. It controls the setting time C. It defines resolution D. It corrects for quantization error

36. What is the primary function of converting a Gray code to a binary code?

A. To encode decimal numbers for storage B. To simplify arithmetic operations by removing carries C. To convert sequential error-minimized codes to standard binary form D. To directly perform addition and subtraction

37. What is the main advantage of using a threshold logic gate over conventional gates?

A. Less sensitive to variations B. More complex with fewer gates required C. Simple to fabricate in IC form D. Processes analog signals only

38. Why are two half adders and one OR gate commonly used to implement a full adder?

A. To reduce the number of total gates needed for addition B. Because a full adder cannot be implemented directly C. It simplifies subtraction operations D. It helps manage carry propagation efficiently

39. Given a D flip flop, how are inputs J and K expressed in terms of D and previous output Qp?

A. J = D, K = D’ B. J = D.Qp, K = D.Qp' C. J = D(1 - Qp), K = D’ Qp D. J = D, K = Qp

40. What is the output expression of an XOR gate with inputs A and B?

A. AB + A’B’ B. A + B C. AB’ + A’B D. (A + B)’

41. Which characteristic of a D/A converter is defined as the reciprocal of the number of discrete output steps?

A. Accuracy B. Resolution C. Setting time D. Monotonicity

42. What is the main difference between SOP and POS Boolean expressions?

A. SOP uses only OR operations, POS uses only AND operations B. SOP sums products, POS products sums C. SOP uses fewer variables than POS D. SOP is used only in combinational circuits, POS in sequential circuits

43. In K-map simplification, what type of grouping reduces complexity most efficiently?

A. Isolated minterms B. Pairs C. Quads or octets (4 or 8 adjacent 1s) D. Single variable terms

44. What is the primary reason an analog input voltage range corresponds to one discrete output level in an ADC?

A. Infinite voltage range B. Quantization levels limit output code resolution C. Signal noise interference D. Input frequency limitations

45. What is the result of binary addition 1 + 1?

A. 2 B. 1 with carry 1 C. 0 with carry 1 D. 10

46. In a 4-bit digital-to-analog converter (DAC), how many distinct output levels are possible?

A. 4 B. 8 C. 16 D. 32

47. The resolution of an ADC refers to:

A. The highest input voltage it can measure B. The smallest change in input voltage that produces a change in output code C. The total number of output codes D. The speed of conversion

48. In an Excess-3 (XS-3) code, which of the following statements is true?

A. It is a weighted BCD code B. Each binary code word is the 8421 code word decreased by 3 C. It is a self-complementing, non-weighted code derived by adding 3 to the 8421 code D. It is used exclusively for error detection

49. Which of the following is a disadvantage of threshold logic gates?

A. They consume excessive power B. Difficult to fabricate and sensitive to parameter variations C. Cannot perform complex Boolean operations D. Limited to two inputs only

50. When converting a decimal fraction to binary, what method is generally used?

A. Successive division by 2 B. Repeated multiplication of the fraction part by 2 C. Direct conversion from decimal to hexadecimal D. Grouping bits into octets