Pseudo Noise Sequence MCQ [Free PDF] – Objective Question Answer for Pseudo Noise Sequence Quiz

11. Which are the design options for an anti-jam communicator?

A. Time diversity
B. Frequency diversity
C. Special discrimination
D. All of the mentioned

Answer: D

The design options for anti-jam communicators are time diversity, frequency diversity, and special discrimination.

 

12. The ratio (J/S)reqd gives the measure of

A. Vulnerability to interference
B. Invulnerability to interference
C. All of the mentioned
D. None of the mentioned

Answer: B

The ratio (J/S)reqd gives the measure of how invulnerable the system is to interference.

 

13. The system should have

A. Larger (J/S)reqd
B. Greater system’s noise rejection capability
C. Larger (J/S)reqd & Greater system’s noise rejection capability
D. None of the mentioned

Answer: C

The system will be efficient if it has greater (J/S)reqd and a larger system’s noise rejection capability.

 

14. The broadband jammer jams the entire

A. W
B. Wss
C. W & Wss
D. None of the mentioned

Answer: B

The broadband jammer or wide-band jammer is the one that jams the entire Wss with its fixed power.

 

15. To increase error probability, the processing gain should be

A. Increased
B. Decreased
C. Exponentially increased
D. Exponentially decreased

Answer: A

In a system, to increase the error probability the processing gain should be increased.

 

16. Which jamming method produces greater degradation?

A. Broadband jamming
B. Partial jamming
C. Broadband & Partial jamming
D. None of the mentioned

Answer: B

Greater degradation is possible more with partial jamming than broadband jamming.

 

17. The jammer which monitors a communicator’s signal is known as

A. Frequency follower jammers
B. Repeat back jammers
C. Frequency follower & Repeat back jammers
D. None of the mentioned

Answer: C

The smart jammers which monitor a communicator’s signals are known as frequency followers or repeat back jammers.

 

17. DS/BPSK includes

A. Despreading
B. Demodulation
C. Despreading & Demodulation
D. None of the mentioned

Answer: C

DS/BPSK is a two-step process that includes despreading and demodulation.

 

18. In the direct sequence process which step is performed first?

A. De-spreading
B. Demodulation
C. Despreading & Demodulation
D. None of the mentioned

Answer: A

In the direct sequence process, the De-spreading correlator is followed by a modulator.

 

19. The processing gain is given as

A. Wss/R
B. R/Wss
C. Wss/2R
D. R/2Wss

Answer: A

The processing gain is given by the ratio of the minimum bandwidth of the data to the data rate.

 

20. Chip is defined as

A. Shortest uninterrupted waveform
B. Largest uninterrupted waveform
C. Shortest diversion
D. None of the mentioned

Answer: A

A chip is defined as the shortest uninterrupted waveform in the system.

 

21. Processing gain is given as

A. Wss/R
B. Rch/R
C. Wss/R & Rch/R
D. None of the mentioned

Answer: C

Processing gain is given both as the ratio of the minimum bandwidth of the data to data rate and also by the ratio of code chip rate and data rate as minimum bandwidth is approximately equal to code chip rate.

 

22. Which modulation scheme is preferred for the direct sequence spread spectrum process?

A. BPSK
B. QPSK
C. BPSK & QPSK
D. None of the mentioned

Answer: C

Both the modulation scheme BPSK and QPSK can be used for the direct sequence spread spectrum process.

 

23. The frequency hopping system uses a ______ modulation scheme.

A. FSK
B. BPSK
C. MFSK
D. MPSK

Answer: C

The frequency-hopping spread spectrum system uses an M-ary frequency-shift keying modulation scheme.

 

24. The minimum spacing between consecutive hop positions gives the

A. Minimum number of chips necessary
B. Maximum number of chips necessary
C. Chip rate
D. None of the mentioned

Answer: A

The minimum spacing between consecutive hop positions gives the minimum number of chips necessary in the frequency word.

 

25. Which system allows larger processing gain?

A. Direct sequence
B. Frequency hopping
C. Direct sequence & Frequency hopping
D. None of the mentioned

Answer: B

The frequency-hopping spread spectrum system allows greater processing gain than the direct sequence spread spectrum technique.

 

26. In which technique is phase coherence hard to maintain?

A. Direct sequence
B. Frequency hopping
C. Direct sequence & Frequency hopping
D. None of the mentioned

Answer: B

In the frequency-hopping spread spectrum phase, coherence is hard to maintain from hop to hop.

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27. Which type of demodulator is used in the frequency hopping technique?

A. Coherent
B. Non-coherent
C. Coherent & Non-coherent
D. None of the mentioned

Answer: B

As it is difficult to maintain phase coherence, a non-coherent demodulator is used.

 

28. Robustness gives the inability of a signal to withstand the impairments.

A. True
B. False

Answer: B

Robustness gives the ability of a signal to withstand the impairments such as noise, jamming, etc.

 

29. Chips are the

A. Repeated symbols
B. Non-repeated symbols
C. Smallest length symbols
D. None of the mentioned

Answer: A

The repeated symbols are called chips.

 

30. Slow frequency hopping is

A. Several hops per modulation
B. Several modulations per hop
C. Several symbols per modulation
D. None of the mentioned

Answer: B

Slow frequency hopping is several modulations per frequency hop.

 

31. Fast frequency hopping is

A. Several modulations per hop
B. Several modulations per symbol
C. Several symbols per modulation
D. None of the mentioned

Answer: D

Fast frequency hopping is several frequency hops per modulation.

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