Digital Communication Test Questions - Set 2

1)   In Adaptive Delta Modulation, the slope error reduces and

a. Quantization error decreases
b. Quantization error increases
c. Quantization error remains same
d. None of the above
Answer  Explanation 

ANSWER: Quantization error increases

Explanation:
No explanation is available for this question!


2)   The number of voice channels that can be accommodated for transmission in T1 carrier system is

a. 24
b. 32
c. 56
d. 64
Answer  Explanation 

ANSWER: 24

Explanation:
No explanation is available for this question!


3)   The maximum data transmission rate in T1 carrier system is

a. 2.6 megabits per second
b. 1000 megabits per second
c. 1.544 megabits per second
d. 5.6 megabits per second
Answer  Explanation 

ANSWER: 1.544 megabits per second

Explanation:
No explanation is available for this question!


4)   T1 carrier system is used

a. For PCM voice transmission
b. For delta modulation
c. For frequency modulated signals
d. None of the above
Answer  Explanation 

ANSWER: For PCM voice transmission

Explanation:
No explanation is available for this question!


5)   Matched filter may be optimally used only for

a. Gaussian noise
b. Transit time noise
c. Flicker
d. All of the above
Answer  Explanation 

ANSWER: Gaussian noise

Explanation:
No explanation is available for this question!


6)   Characteristics of Matched filter are

a. Matched filter is used to maximize Signal to noise ratio even for non Gaussian noise
b. It gives the output as signal energy in the absence of noise
c. They are used for signal detection
d. All of the above
Answer  Explanation 

ANSWER: All of the above

Explanation:
No explanation is available for this question!


7)   Matched filters may be used

a. To estimate the frequency of the received signal
b. In parameter estimation problems
c. To estimate the distance of the object
d. All of the above
Answer  Explanation 

ANSWER: All of the above

Explanation:
No explanation is available for this question!


8)   The process of coding multiplexer output into electrical pulses or waveforms for transmission is called

a. Line coding
b. Amplitude modulation
c. FSK
d. Filtering
Answer  Explanation 

ANSWER: Line coding

Explanation:
No explanation is available for this question!


9)   For a line code, the transmission bandwidth must be

a. Maximum possible
b. As small as possible
c. Depends on the signal
d. None of the above
Answer  Explanation 

ANSWER: As small as possible

Explanation:
No explanation is available for this question!


10)   Regenerative repeaters are used for

a. Eliminating noise
b. Reconstruction of signals
c. Transmission over long distances
d. All of the above
Answer  Explanation 

ANSWER: All of the above

Explanation:
No explanation is available for this question!


11)   Scrambling of data is

a. Removing long strings of 1's and 0's
b. Exchanging of data
c. Transmission of digital data
d. All of the above
Answer  Explanation 

ANSWER: Removing long strings of 1's and 0's

Explanation:
No explanation is available for this question!


12)   In polar RZ format for coding, symbol '0' is represented by

a. Zero voltage
b. Negative voltage
c. Pulse is transmitted for half the duration
d. Both b and c are correct
Answer  Explanation 

ANSWER: Both b and c are correct

Explanation:
No explanation is available for this question!


13)   In a uni-polar RZ format,

a. The waveform has zero value for symbol '0'
b. The waveform has A volts for symbol '1'
c. The waveform has positive and negative values for '1' and '0' symbol respectively
d. Both a and b are correct
Answer  Explanation 

ANSWER: Both a and b are correct

Explanation:
No explanation is available for this question!


14)   Polar coding is a technique in which

a. 1 is transmitted by a positive pulse and 0 is transmitted by negative pulse
b. 1 is transmitted by a positive pulse and 0 is transmitted by zero volts
c. Both a & b
d. None of the above
Answer  Explanation 

ANSWER: 1 is transmitted by a positive pulse and 0 is transmitted by negative pulse

Explanation:
No explanation is available for this question!


15)   The polarities in NRZ format use

a. Complete pulse duration
b. Half duration
c. Both positive as well as negative value
d. Each pulse is used for twice the duration
Answer  Explanation 

ANSWER: Complete pulse duration

Explanation:
No explanation is available for this question!


16)   The format in which the positive half interval pulse is followed by a negative half interval pulse for transmission of '1' is

a. Polar NRZ format
b. Bipolar NRZ format
c. Manchester format
d. None of the above
Answer  Explanation 

ANSWER: Manchester format

Explanation:
No explanation is available for this question!


17)   The maximum synchronizing capability in coding techniques is present in

a. Manchester format
b. Polar NRZ
c. Polar RZ
d. Polar quaternary NRZ
Answer  Explanation 

ANSWER: Manchester format

Explanation:
No explanation is available for this question!


18)   The advantage of using Manchester format of coding is

a. Power saving
b. Polarity sense at the receiver
c. Noise immunity
d. None of the above
Answer  Explanation 

ANSWER: Power saving

Explanation:
No explanation is available for this question!


19)   Alternate Mark Inversion (AMI) is also known as

a. Pseudo ternary coding
b. Manchester coding
c. Polar NRZ format
d. None of the above
Answer  Explanation 

ANSWER: Pseudo ternary coding

Explanation:
No explanation is available for this question!


20)   In Alternate Mark Inversion (AMI) is

a. 0 is encoded as positive pulse and 1 is encoded as negative pulse
b. 0 is encoded as no pulse and 1 is encoded as negative pulse
c. 0 is encoded as negative pulse and 1 is encoded as positive pulse
d. 0 is encoded as no pulse and 1 is encoded as positive or negative pulse
Answer  Explanation 

ANSWER: 0 is encoded as no pulse and 1 is encoded as positive or negative pulse

Explanation:
No explanation is available for this question!