LFSR & Sequence Generators MCQs

Practice LFSR & Sequence Generators MCQs with four options, answers and explanations for focused Electronics & Telecommunication Engineering revision.

Question 1

Digital ElectronicsLFSR & Sequence Generators

What is the maximum sequence length of a properly configured 4-stage maximal-length LFSR?

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Correct Answer: C. 15

Explanation: For n=4, a maximal-length LFSR period is 2^4−1=15 states.

Reference: Standard digital electronics: LFSR period

Question 2

Digital ElectronicsLFSR & Sequence Generators

Why is the all-zero state normally excluded from an XOR-feedback LFSR sequence?

AIt can become a locked state that continues producing zeros
BIt causes the supply voltage to double
CIt automatically changes to all ones
DIt destroys the clock generator

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Correct Answer: A. It can become a locked state that continues producing zeros

Explanation: With XOR feedback, an all-zero register generally produces zero feedback, so every subsequent state remains all zero unless external logic forces the LFSR out of that state.

Reference: Standard digital electronics: LFSR lock state

Question 3

Digital ElectronicsLFSR & Sequence Generators

A maximal-length n-stage linear feedback shift register (LFSR), when configured with a primitive feedback polynomial and excluding the all-zero lock state, cycles through how many nonzero states?

An
B2n
C2^n - 1
D2^n

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Correct Answer: C. 2^n - 1

Explanation: A maximal-length LFSR generates a pseudorandom sequence containing every nonzero n-bit state once per period, giving 2^n−1 states.

Reference: Standard digital electronics: maximal-length LFSR