Practical Aspects and Testability of VLSI MCQ Quiz – Objective Question with Answer Practical Aspects and Testability for

231. The type of errors in the self-checking techniques is

A. simple error
B. unidirectional error
C. multiple errors
D. all of the mentioned

Answer: D

The type of errors in self-checking techniques are simple errors, unidirectional errors, and multiple errors.

 

232. The parity check detection is done using

A. OR gate
B. AND gate
C. XOR gate
D. NOR gate

Answer: C

The parity check detects simple errors using XOR gates and for each type of error, the approximate coding technique is used.

 

233. Which errors are detected using duplication codes?

A. single errors
B. unidirectional errors
C. bidirectional errors
D. multiple errors

Answer: D

Multiple errors are detected using duplication codes which consist of duplicating the information.

 

234. Linear feedback shift register occupies more area.

A. true
B. false

Answer: B

The linear feedback shift register method is more area efficient than counters and other methods and requires less combinational logic.

 

235. In external feedback LFSR, shift registers and feedback paths are combined using

A. OR gates
B. AND gates
C. EX-OR gates
D. NAND gates

Answer: C

In the external feedback linear feedback shift register method, the shift registers, and the feedback path are linearly combined via EX-OR gates.

 

236. Which uses the highest operating frequency?

A. internal feedback LFSR
B. external feedback LFSR
C. both internal and external LFSR
D. counters

Answer: A

Internal feedback LFSR provides implementation with the highest operating frequency for use in high-performance applications.

 

237. Which method has more uniformity?

A. internal feedback LFSR
B. external feedback LFSR
C. all of the mentioned
D. none of the mentioned

Answer: B

External feedback LFSR has more uniformity of the shift register and this is its main advantage.

 

238. The initial state in LFSR must be initialized to zero.

A. true
B. false

Answer: B

The initial state in LFSR must be initialized to any state other than zero so that it goes through all possible states except all 0’s before repeating the sequence.

 

239. For n-bit LFSR, the longest possible sequence is given by

A. 2n
B. 2n + 1
C. 2n – 1
D. 1/2n

Answer: C

For n-bit LFSR, the longest possible sequence of patterns is given by 2n-1.

 

240. ______ determines the position of the EX-OR gate with respect to flip-flops.

A. maximal length sequence
B. value of n
C. number of flip-flops
D. characteristic equation

Answer: D

The placement of EX-OR gates with respect to the flip-flops in LFSR is determined using the characteristic polynomial equation.

 

241. The zero coefficient terms determine the number of EX-OR gates to be used.

A. true
B. false

Answer: B

The non-zero coefficient in the characteristic polynomial expresses the EX-OR gate in the feedback network.

 

242. LFSR has ______ gates.

A. EX-OR gates
B. AND gates
C. OR gates
D. EX-OR and AND gates

Answer: A

LFSR has flip-flops and EX-OR gates and counters have one EX-OR gate and AND gate per flip-flop.

 

243. Primitive polynomials are those

A. which has an initial state of zero
B. which gives maximal length sequence
C. which does not give maximal length sequence
D. which has AND gate per flip-flop

Answer: B

Primitive polynomials are those which give maximal length sequence and those which do not give maximal length sequence are called a non-primitive polynomial.

 

244. In LFSR, the test patterns are repeatable.

A. true
B. false

Answer: A

In the linear feedback shift register used to produce pseudo-random patterns, the patterns are deterministically generated and are repeatable.

 

245. The primitive polynomial should have a minimum number of zero coefficients.

A. true
B. false

Answer: A

Primitive polynomials with a minimum number of zero coefficients are the desired characteristic polynomial for the LFSR.

 

246. The minimum number of EX-OR gates used is in between

A. 0 to 2
B. 1 to 3
C. 2 to 5
D. 3 to 7

Answer: B

The minimum number of EX-OR gates used for the linear feedback shift register is between 1 and 3.

 

247. The LFSR takes reasonable time if the n value is

A. below 50
B. below 100
C. below 10
D. below 25

Answer: D

The LFSR’s degree value is limited to 22 to 25 for producing maximal length sequence in a reasonable amount of time.

 

248. Which is used to initialize the LFSRs?

A. zeroes
B. ones
C. preset of flip-flop
D. EX-OR gate

Answer: C

The preset of each flip-flop in LFSR to used to initialize the LFSRs and the initial non-zero coefficient or state ensures maximal length sequence is obtained.

 

249. The beginning and end of the maximal length sequence can be determined using

A. AND gate
B. NAND gate
C. AND or NAND gate
D. Both AND and NAND gate

Answer: C

The beginning and end of the maximal length sequence of the LFSR can be determined using AND gate or NAND gate.

 

250. Preloading different starting values for the LFSR is called as

A. seeding
B. reseeding
C. deseeding
D. pre-seeding

Answer: B

Initializing with a specific value to the LFSR is called as seeding and preloading different starting value is called reseeding.

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