Question 1

Which of the following is a disadvantage of tone-in-band SSB system?

Accepted Answer

A)  high bandwidth
B)  bad adjacent channel protection
C)  effects of multipath
D)  generation and reception of signal is complicated D

Question 2

Why frequency fogging is used in a carrier system?

Accepted Answer

A)  to reduce noise
B)  to reduce cross talk
C)  to converge frequencies
D)  to reduce distortion B

Question 3

In AM pilot carrier, transmission has

Accepted Answer

A)  carrier and part of one side band
B)  two side bands and a carrier
C)  two side bands
D)  carrier, one side band and part of other side band B

Question 4

The performance of modulation scheme is not measured in terms of_________

Accepted Answer

A)  power efficiency
B)  bandwidth efficiency
C)  cost and complexity
D)  transmitted power

Question 5

Which of the following is defined as the range of frequencies over which the signal has a non zero power spectral density?

Accepted Answer

A)  null to null bandwidth
B)  half power bandwidth
C)  3 db bandwidth
D)  absolute bandwidth

Question 6

Single sideband AM systems occupy same bandwidth as of conventional AM systems.

Accepted Answer

A) True 
 B)False

Question 7

What is the use of Companding?

Accepted Answer

A)  in pcm transmitters to allow amplitude limiting in the receivers
B)  in pcm receiver to overcome impulse noise
C)  to overcome quantizing noise in pcm
D)  to protect small signals in pcm from quantizing distortion

Question 8

Which of the following are two methods for generating FM signal?

Accepted Answer

A)  coherent method, noncoherent method
B)  product detector, envelope detector
C)  direct method, indirect method
D)  slope detector, zero crossing detector

Question 9

5 PSD MODULATORS AND DEMODULATORS

Accepted Answer

A) True 
 B)False

Question 10

is equal to width of main spectral lobe.

Accepted Answer

A)  null to null bandwidth
B)  half power bandwidth
C)  3 db bandwidth
D)  absolute bandwidth

Question 11

VSB modulation is used in televisions because it avoids phase distortion at low frequencies.

Accepted Answer

A) True 
 B)False

Question 12

A product detector in AM systems is also called_________

Accepted Answer

A)  envelope detector
B)  differentiator
C)  integrator
D)  phase detector

Question 13

What is the frequency of the stereo sub carrier signal in FM broadcasting?

Accepted Answer

A)  19 khz
B)  45 khz
C)  55 khz
D)  38 khz

Question 14

Which of the following is used to vary the frequency of the carrier frequency in accordance with the baseband signal amplitude variations in direct method of FM generation?

Accepted Answer

A)  integrator
B)  envelope detector
C)  multivibrator
D)  voltage controlled oscillators

Question 15

FM is a part of general class of modulation known as_________

Accepted Answer

A)  angle modulation
B)  phase modulation
C)  amplitude modulation
D)  frequency modulation

Question 16

In indirect method, the carrier frequency is directly varied in accordance with the input modulating signal.

Accepted Answer

A) True 
 B)False

Question 17

AM system use only product detector for demodulation. They never use envelope detectors.

Accepted Answer

A) True 
 B)False

Question 18

What do you understand by the term "carrier" in modulation?

Accepted Answer

A)  voltage to be transmitted
B)  resultant wave
C)  voltage for which amplitude, phase or frequency can be varied
D)  voltage for which amplitude, phase or frequency remains constant

Question 19

The frequency deviation is proportional to frequency in phase modulated signal.

Accepted Answer

A) True 
 B)False

Question 20

Which of the following is the ratio of signal energy per bit to noise power spectral density?

Accepted Answer

A)  bandwidth efficiency
B)  spectral density
C)  power efficiency
D)  power density

Exam 1: Modulation and Demodulation Techniques

Which of the following is a disadvantage of tone-in-band SSB system?

Why frequency fogging is used in a carrier system?

In AM pilot carrier, transmission has

The performance of modulation scheme is not measured in terms of_________

Which of the following is defined as the range of frequencies over which the signal has a non zero power spectral density?

Single sideband AM systems occupy same bandwidth as of conventional AM systems.

What is the use of Companding?

Which of the following are two methods for generating FM signal?

5 PSD MODULATORS AND DEMODULATORS

is equal to width of main spectral lobe.

VSB modulation is used in televisions because it avoids phase distortion at low frequencies.

A product detector in AM systems is also called_________

What is the frequency of the stereo sub carrier signal in FM broadcasting?

Which of the following is used to vary the frequency of the carrier frequency in accordance with the baseband signal amplitude variations in direct method of FM generation?

FM is a part of general class of modulation known as_________

In indirect method, the carrier frequency is directly varied in accordance with the input modulating signal.

AM system use only product detector for demodulation. They never use envelope detectors.

What do you understand by the term "carrier" in modulation?

The frequency deviation is proportional to frequency in phase modulated signal.

Which of the following is the ratio of signal energy per bit to noise power spectral density?