VLSI Multiple Choice Questions on “Cellular Automata”.
1. Cellular automata produce
A. exhaustive patterns
B. exhaustive pseudo random patterns
C. random patterns
D. pseudo random patterns
Answer: D
Clarification: Cellular automata is similar to linear feedback shift register and it generates pseudo-random patterns.
2. In which method the effect of bit shifting is not observed or visible?
A. internal feedback LFSR
B. external feedback LFSR
C. cellular automata
D. counters
Answer: C
Clarification: The effect of bit shifting is not observed in cellular automata as it is done in linear feedback shift register.
3. The patterns produced using ______ is less random.
A. LFSR
B. Cellular automata
C. NAND gates
D. Shift registers
Answer: A
Clarification: The patterns produced by cellular automata is more random in nature than those produced using LFSR.
4. Which method needs more number of EX-OR gates?
A. internal feedback LFSR
B. counters
C. external feedback LFSR
D. cellular automata
Answer: D
Clarification: The construction of cellular automata is not as simple as LFSR and thus cellular automata needs more number of EX-OR gates.
5. The construction of CA register is based on
A. logical relationship of flip-flop
B. EX-OR gate
C. primitive polynomial
D. degree of the polynomial
Answer: A
Clarification: The construction of cellular automata is based on the logical relationship of each flip-flop to its two neighbours.
6. The next state for rule 150 is obtained by
A. x(t)
B. x(t+1)+x(t)+x(t-1)
C. x(t+1)+x(t-1)
D. x(t)+x(t-1)
Answer: B
Clarification: The next state for rule 150 is obtained by exploring three current state values – itself, previous flip-flop and next flip-flop.
7. The next state for rule 90 is obtained by
A. x(t)
B. x(t+1)+x(t)+x(t-1)
C. x(t+1)+x(t-1)
D. x(t)+x(t-1)
Answer: C
Clarification: The next state for rule 90 is obtained by exploring two current values – the state value of previous and the next flip-flop.
8. Which occupies lesser area?
A. internal feedback LFSR
B. external feedback LFSR
C. null condition CA
D. cyclic boundary CA
Answer: D
Clarification: The area occupied by null boundary cellular automata is comparatively lesser than that used by cyclic boundary CA.
9. The maximal length sequence is given by
A. 2n
B. 2n + 1
C. 2n – 1
D. 2n
Answer: C
Clarification: The maximal length sequence is given by 2n – 1 in null condition boundary cellular automata.
10. Rule 90 CA minimizes area when compared to rule 150.
A. true
B. false
Answer: A
Clarification: Maximizing the use of rule 90 cellular automata minimizes area overhead when compared to using rule 150 cellular automata.