Digital electronics revision unit4 mcq

ASYNCHRONOUS SEQUENTIAL CIRCUIT -SAMPLE-MULTIPLE CHOISE BASED QUESTION & ANSWERS-

1. MCQ Prepared Ms. P.Sivalakshmi AP/ECE/RMKCET Digital Electronics Revision class (unit-4)

2. Sample Part A MCQ Inputs are levels and not pulses for Fundamental mode circuit True False Inputs are levels and not pulses for Pulse mode circuit True False When an asynchronous circuit makes a transition through a series of unstable states. a) Cycles b ) Races

3. 4. In _________sequential circuits, memory elements are either Unclocked flip-flops or time delay elements. Asynchronous sequential circuits. Synchronous sequential circuits 5 . In _________sequential circuits, memory elements are clocked flip-flops. a)Asynchronous sequential circuits. b)Synchronous sequential circuits 6 . Unequal delays means in the signal path of the circuit. Glitch Race Sample Part A MCQ

4. Sample Part A MCQ 7.The different techniques used in state assignment Share row state assignment One hot state assignment a ) i only b ) ii only c) i and ii 8.In a combinational circuit, if output goes momentarily 0 when it should remain a 1, the hazard is known a ) Static 0 b) Static 1 9.In a combinational circuit, if output goes momentarily 1 when it should remain a 0, the hazard is known a)Static b)Static 1

5. 10.If output changes three or more times when it should change from 1 to 0 or from 0 to 1. Static-1 hazard Static-0 hazard Dynamic hazard Sample Part A MCQ 11. An __________ hazard is caused by unequal delays along two or more paths that originate from the same input. Such hazard can be eliminated by adjusting the amount of delays in the affected path. Static-1 hazard Static-0 hazard Essential hazard

6. 1. Give hazard-free realization for the following Boolean functions. 𝑓(𝐴, 𝐵, 𝐶, 𝐷) = ∑ m (0,1,5,6,7,9,11) F= ᾹB̄ C̄ + AB̄ D + B̄ C̄ D + ᾹC̄ D + ᾹBD + ᾹBC F= ABC + ᾹB̄ D + B̄ C̄ D + ᾹC̄ D F= ᾹBD + AB̄ C F= B̄ C̄ D + ᾹC̄ D + ᾹBD + ᾹBC Sample Part B MCQ 2. Table that is not a part of asynchronous analysis procedure is transition table state table c) flow table d ) excitation table

7. 3. The present states and next state of asynchronous circuits are also called secondary variables primary variables excitation variables Short term memory 4. The race in which stable state depends on order is called critical race identical race non critical race defined race Sample Part B MCQ

8. Sample Part B MCQ 5. Each logic gate gives delay of 1 to 5 ns 2 to 10 ns 3 to 10 ns 3 to 5 ns 6. The complexity of asynchronous circuit is involved in timing problems of Inputs Outputs Clock pluses feedback path 7. Table that is not a part of asynchronous analysis procedure is transition table state table

9. Sample Part B MCQ 8. ASM chart represents Gates Multiplexers Synchronous sequential circuits PLAs 9. An algorithmic state machine consists of Only gates Only multiplexers Combinational circuits and flip-flops Only flip-flops 10. An algorithmic state machine is the same as Synchronous sequential circuit Clocked sequential circuit Finite state machine All of the above

10. 11.Match the following sequential Circuits with associated functions 1. Counter -------- A. Storage of Program & data in a digital computer 2. Register -------- B. Generation of timing variables to sequence the digital system operations 3. Memory --------- C. Design of Sequential Circuits Codes: a. 1-A , 2-B , 3-C b. 1-C , 2-B , 3-A c. 1-C , 2-A , 3-B d. 1-B , 2-C , 3-A Sample Part B MCQ

11. Sample Part B MCQ 12.Which memory elements are utilized in an asynchronous & clocked sequential circuits respectively? a. Time- delay devices & registers b. Time- delay devices & flip-flops c. Time- delay devices & counters d. Time-delay devices & latches

12. 13. Internal states and input values together are called a. Full state b. Total state c. Initial state d. Output state 14. The behavior of synchronous sequential circuit can be predicted by defining the signals at ______. a. discrete instants of time b . continuous instants of time c. sampling instants of time d . at any instant of time Sample Part B MCQ

13. 15.Asynchronous sequential logic circuits are used when a primary need is a. Time b. Pressure c. Speed d. Accuracy Sample Part B MCQ

14. THANK YOU