# Communication Engineering Mock Test

30 Questions | Total Attempts: 53  Settings  .

• 1.
In the Amplitude modulated wave ____________carries the the majority power from the transmitter to the receiver
• A.

Carrier

• B.

USB

• C.

LSB

• D.

Both USB and LSB

• 2.
Degree of modulation depends on---------
• A.

Only amplitude of carrier

• B.

Only amplitude of modulating wave

• C.

Amplitude of both carrier and modulating wave

• D.

Amplitude of both carrier and modulated wave

• 3.
Identify the source of transmission in the case of radio transmission
• A.

Antenna

• B.

Space

• C.

Cable

• D.

Coaxial

• 4.
At which stage the noise is generally developed in the case of radio type receivers?
• A.

IF Stage

• B.

Receiving antenna

• C.

RF stage

• D.

Audio stage

• 5.
Calculate the modulation index if the three modulating signals are having modulation index of 0.6, 0.3, 0.4
• A.

0.871

• B.

0.781

• C.

0.178

• D.

0.117

• 6.
What is the Bandwidth of FM in which the modulating signal is 2 KHZ and the maximum frequency deviation is 12 KHZ. Use Carson's rule.
• A.

26 KHZ

• B.

20 KHZ

• C.

28 KHZ

• D.

30 KHZ

• 7.
Identify the Characteristics of Narrow Band FM
• A.

The frequency sensitivity kf is large and Bandwidth is wide

• B.

The frequency sensitivity kf is small and Bandwidth is narrow

• C.

The frequency  sensitivity kf is large and Bandwidth is narrow

• D.

The frequency sensitivity kf is small and Bandwidth is wide

• 8.
Pick the incorrect choice in the analog communication system
• A.

• B.

Frequency division multiplexing

• C.

A/D converter

• D.

Prone to noise

• 9.
In radio transmission, for the height of antenna to be 90m, what should be the modulated signal in AM broadcasting?
• A.

8 MHZ

• B.

80 MHZ

• C.

0.8 MHZ

• D.

30 MHZ

• 10.
Find the bandwidth of the following multitone amplitude modulation system. Given modulating frequencies are 2 kHz and 5 kHz with carrier frequency of 1MHz.
• A.

3 kHz

• B.

7 kHz

• C.

10 kHz

• D.

1005 kHz

• 11.
What is the image frequency for a standard broadcast AM superheterodyne receiver tuned to a station at 700 kHz?
• A.

1610 kHz

• B.

1155 kHz

• C.

245 kHz

• D.

945 kHz

• 12.
• A.

For entire frequency range large variation in bandwidth

• B.

There is instability since amplifiers tuned to same carrier frequency

• C.

Variations in gains of RF amplifiers

• D.

Not capable of receiving and detecting weak RF signals

• 13.
The total antenna current of an AM transmitter is 10A. If modulation index is 0.8, calculate the carrier current in antenna
• A.

3.2

• B.

4.6

• C.

8.7

• D.

9.5

• 14.
Changing the Characteristics of the sinusoidal Carrier signal with respect to digital input signal is known as
• A.

Analog modulation

• B.

Encoding

• C.

Digital Modulation

• D.

Demodulation

• E.

None of the above

• 15.
In BPSK , the symbols 1 and 0 are denoted by carrier wave with phase shift of
• A.

π/2

• B.

• C.

π

• D.

0

• 16.
The minimum bandwidth to send an information without loss is called
• A.

Trellis Bandwidth

• B.

Nyquist Bandwidth

• C.

Shannon limit

• D.

Huffman Bandwidth

• 17.
The ability of the receiver to select the wanted signals among the various incoming signals is termed as
• A.

Sensitivity

• B.

Selectivity

• C.

Stability

• D.

Fiedility

• 18.
The amount of data transmitted for a given amount of time is called
• A.

Bandwidth

• B.

Frequency

• C.

Noise

• D.

Signal power

• 19.
• A.

Have better sensitivity

• B.

Have high selectivity

• C.

Need extra circuitry for frequency conversion

• 20.
Standard intermediate frequency used for AM receiver is
• A.

455 MHz

• B.

455 KHz

• C.

455 Hz

• 21.
The modulation technique that uses the minimum channel bandwidth and transmitted power is
• A.

FM

• B.

DSB-SC

• C.

VSB

• D.

SSB

• 22.
The total power in an Amplitude Modulated signal if the carrier of an AM transmitter is 800 W and it is modulated 50 percent.
• A.

850 W

• B.

1000.8 KW

• C.

750 W

• D.

900 W

• 23.
A 100MHz carrier is frequency modulated by 10 KHz wave. For a frequency deviation of 50 KHz, calculate the modulation index of the FM signal.
• A.

100

• B.

50

• C.

70

• D.

90

• 24.
FM is disadvantageous over AM signal because
• A.

Much wider channel bandwidth is required

• B.

FM systems are more complex and costlier

• C.

• 25.
FSK reception is
• A.

Phase Coherent

• B.

Phase non coherent

• C.

Phase Coherent & non coherent

• D.

None of the mentioned Back to top