Communications MCQ Set 1
1. TRF receivers are used for ________
a) Detection of modulating signal
b) Removal of unwanted signal
c) Removing noise
d) Both detection of modulating signal and removal of unwanted signal
2. Calculate the power in a DSB-SC signal, if the modulation is 60% and power of carrier wave is 600W?
3. One of the advantage of using analog communication over digital communication is that in analog communication less transmission bandwidth is required?
4. According to Fourier analysis, square wave can be represented as ________
a) fundamental sine wave and even harmonics
b) fundamental sine wave and odd harmonics
c) fundamental sine wave and harmonics
d) fundamental and sub harmonic sine wave
5. What is the maximum transmission efficiency of an AM signal?
6. Mass of any moving system is represented by ________
a) a resistance
b) a conductance
c) combination of inductor and capacitor
d) an inductance
7. Generation of SSB-SC signal is done by ________
a) Phase discrimination method and Frequency discrimination method
b) Phase discrimination method and Product modulator
c) Product modulator and Frequency discrimination method
d) Product modulator and Square law modulator
8. Bandwidth of RF amplifier for a color TV receiver is ________
a) equal to channel width
b) more than channel width
c) less than channel width
d) twice of channel width
9. In automatic gain control of the AM receiver ________
a) gain of the receiver is adjusted
b) gain adjustment depends upon the strength of received signal
c) output provided is an AC voltage
d) required power is very low
10. Which of the following is an example of continuous wave analog modulation?
Communications MCQ Set 2
1. What is the purpose of peak clipper circuits in radios?
a) prevent overmodulation
b) reduce bandwidth
c) increase bandwidth
d) regulate oscillator input voltage
2. In FM receiver, role of amplitude limiter is to reduce the amplitude of signals.
3. Balanced modulator is used to suppress carrier signal to create a SSB or DSB.
4. A noiseless Gaussian channel has _____________
a) zero capacity
b) small capacity
c) infinite capacity
d) can’t be determined
5. What is the main function of a balanced modulator?
a) to limit the noise picked by a receiver
b) to produce balanced modulation of a carrier wave
c) to suppress carrier signal
d) to produce 100% modulation
6. For classifying a modem as low speed its data rate is ________
a) upto 100bps
b) upto 200bps
c) upto 400bps
d) upto 600bps
7. Varacter diode modulator is an indirect way of generating FM.
8. Which of the following is an indirect way of generating FM?
a) By reactance modulator
b) By bipolar transistor
c) By varacter diode
d) By armstrong modulator
9. Convex lens has negative focal power and concave lens have positive focal power.
10. All lens have positive focal power.
Communications MCQ Set 3
1. Which is the standard reference antenna for the directive gain?
a) Isotropic antenna
b) Marconi antenna
c) Helical antenna
d) Log Periodic antenna
2. Which one of the following reasons for the use of a ground screen with antennas is false?
a) Impossibility of a good ground connection
b) Provision of an earth for the antenna
c) Protection of personnel working underneath
d) Improvement of radiation pattern of antenna
3. Which of the following antennas is best excited from a waveguide?
4. An ungrounded antenna near the ground ________
a) must be horizontally polarized
b) acts as an antenna array
c) is unlikely to need a ground screen
d) acts as a single antenna of twice the height
5. Field strength at a distance from an antenna is measured with __________
a) a slotted line
b) a dipole
c) an EIRP meter
d) a field strength meter
6. The radiated beam from a parabolic “dish” transmitting antenna is ________
7. Power density spectrum of a resistor R can be expressed as ________
a) 2 kTR
b) 1 kTR
c) 0.75 kTR
d) 3 kTR
8. What is the full form of LPDA?
a) Log Periodic Dipole Array
b) Log Power Dipole Array
c) Low Periodic Dipole Array
d) Low Power Dipole Array
9. Arrays in antenna can be __________
d) phased, driven or parasitic
10. What is the typical bandwidth of a 2-wire telephone line?
a) 20 Hz to 6 KHz
b) 300 Hz to 3.4 KHz
c) 20 Hz to 20 KHz
d) 200 Hz to 6.5 KHz
Communications MCQ Set 4
1. A 1000KHz carrier is modulated by 100Hz and 200Hz waves, then which of the following frequencies cannot be present at the output?
2. Aspect ratio is the ratio of ________
a) width to height
b) height to width
c) power to width
d) width to power
3. If the levels in PCM are transmitted in 10 unit code having sampling frequency equals to 20KHz. What is its bandwidth?
4. Carrier frequency is given by the formula ________
5. Among all amplifiers, Common Collector has highest power gain.
6. Find the carrier frequency if the inductance and capacitance are 30μH and 10nF respectively?
7. Helical antenna is used to obtain ________ polarization.
8. What is number of possible outputs if there is 6 line digital input?
9. Push pull amplifier is a class B amplifier.
10. For removing unwanted signals we should use ________
a) phase shift method
b) filteration ethod
c) distillation method
d) elimination method
Communications MCQ Set 5
1. If we compared to the core, the index of refraction of cladding must be ________
d) can be greater or less
2. What is used in making single-mode fiber?
3. A single-mode cable does not suffer from?
a) chromatic dispersion
b) waveguide dispersion
c) modal dispersion
d) complex dispersion
4. ISI stands for ________
a) Inter Symbol Interference
b) Inter Signal Interference
c) Inter System Interference
d) Inter Service Interference
5. FDDI stands for __________
a) Fiber Digital Data Interface
b) Fiber Digital Delay Interface
c) Fiber Distributed Data Interface
d) Fiber Distributed Delay Interface
6. What you understand by the term Soliton?
a) it is a defect in the glass
b) it is a type of particle
c) it is a type of pulse
d) it is a type of optical network
7. Signal to noise ratio is calculated as signal voltage divided by noise voltage.
8. Which statement is true about varacter?
a) it is a diode
b) it is a voltage-controlled capacitor
c) it is used in tuned circuits
d) it is a diode used in tuned circuit and also has a voltage-controlled capacitor
9. A frequency synthesizer is _________
a) A VCO phase locked to a reference frequency
b) A VFO phase locked to a reference frequency
c) A fixed frequency RF generator
d) A variable frequency RF generator
10. Why CSMA/CD network has a minimum length for packets?
a) to increase the data rate
b) to decrease the data rate
c) to prevent packets from reaching all other nodes
d) to make sure that all other nodes hear a collision in progress