Deck 9: Algorithms and Techniques for Communication System Security and Error Correction

Question 1

In comparison to stack algorithm, Fano's algorithm is simpler.

Answer 1

False

Question 2

Which of the following is not an error correction and detection code?

A)block code
B)convolutional codes
C)passive codes
D)turbo codes

Answer 2

passive codes

Question 3

Which decoding method involves the evaluation by means of Fano's algorithm?

A)maximum likelihood decoding
B)sequential decoding
C)maximum a priori
D)minimum mean square

Answer 3

sequential decoding

Question 4

In Viterbi's algorithm, the selected paths are regarded as_________          

A)survivors
B)defenders
C)destroyers
D)carriers

Question 5

Pseudorandom signal_________      predicted.

A)can be
B)cannot be
C)maybe
D)none of the mentioned

Question 6

The properties used for pseudorandom sequence are

A)balance
B)run
C)correlation
D)all of the mentioned

Question 7

The shift register needs to be controlled by clock pulses.

Question 8

A linear feedback shift register consists of

A)feedback path
B)modulo 2 adder
C)four stage register
D)all of the mentioned

Question 9

If the initial pulse of 1000 is fed to shift register, after how many clock pulses does the sequence repeat?

A)15
B)16
C)14
D)17

Question 10

The sequences produced by shift register depends on

A)number of stages
B)feedback tap connections
C)initial conditions
D)all of the mentioned

Question 11

For maximal length sequence, the sequence repetition clock pulses p is given by

A)2n + 1
B)2n -1
C)2n
D)none of the mentioned

Question 12

For any cyclic shift, the auto-correlation function is equal to

A)1/p
B)-1/p
C)-p
D)p

Question 13

Which method is better?

A)to share same bandwidth
B)to share different bandwidth
C)to share same & different bandwidth
D)none of the mentioned

Question 14

Pulse jammer consists of

A)pulse modulated excess band noise
B)pulse modulated band-limited noise
C)pulse width modulated excess band noise
D)pulse width modulated band-limited noise

Question 15

Which are the design options for anti jam communicator?

A)time diversity
B)frequency diversity
C)special discrimination
D)all of the mentioned

Question 16

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

Question 17

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

Question 18

The broadband jammer jams the entire

A)w
B)wss
C)w & wss
D)none of the mentioned

Question 19

To increase error probability, the processing gain should be

A)increased
B)decreased
C)exponentially increased
D)exponentially decreased

Question 20

Which jamming method produces greater degradation?

A)broadband jamming
B)partial jamming
C)broadband & partial jamming
D)none of the mentioned

Question 21

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

Question 22

DS/BPSK includes

A)despreading
B)demodulation
C)despreading & demodulation
D)none of the mentioned

Question 23

In direct sequence process which step is performed first?

A)de-spreading
B)demodulation
C)despreading & demodulation
D)none of the mentioned

Question 24

Chip is defined as

A)shortest uninterrupted waveform
B)largest uninterrupted waveform
C)shortest diversion
D)none of the mentioned

Question 25

Processing gain is given as

A)wss/r
B)rch/r
C)wss/r & rch/r
D)none of the mentioned