Electrical Engineering · Question Bank

Communications

408 questions · page 16 of 21. Answer in your head first, then check the solution.

📘 EE Mock Board Exam
#301
What is the frequency range for CB radio with 40 channels?
A26.965 to 27.405 MHz
B31.270 to 42.575 MHz
C18.560 to 20.145 MHz
D40.785 to 53.090 MHz
#302
International Distress Frequency ________
A100 kHz
B400 kHz
C500 kHz
D200 kHz
#303
CMOS inverter consists of how many transistors?
A2
B4
C3
D10
#304
It is the instantaneous change in phase of the carrier at a given instant of time and indicates how much phase of the carrier is changing with respect to its reference phase
Ainstantaneous frequency
Binstantaneous frequency deviation
Cinstantaneous phase
Dinstantaneous phase deviation
#305
It is the precise phase of the carrier at a given instant of time
Ainstantaneous phase deviation
Binstantaneous phase
Cinstantaneous frequency deviation
Dinstantaneous frequency
#306
It is the instantaneous change in frequency of the carrier and is defined as the first time derivative of the phase deviation
Ainstantaneous frequency
Binstantaneous frequency deviation
Cinstantaneous phase
Dinstantaneous phase deviation
#307
It is the precise frequency of the carrier at a given instant of time is defined as the first time derivative of the instantaneous phase
Ainstantaneous frequency
Binstantaneous frequency deviation
Cinstantaneous phase deviation
Dinstantaneous phase
#308
It is the output-versus-input transfer functions for modulators which give the relationship between the output parameter changes in respect to specified changes in respect to specified changes in the input signal
Afrequency deviation
Bdeviation sensitivity
Ctransconductance curve
Dphase deviation
#309
In PM, carrier frequency deviation is not proportional to:
Amodulating signal amplitude
Bcarrier amplitude and frequency
Cmodulating signal frequency
Dmodulator phase shift
#310
To compensate for increases in carrier frequency deviation with an increase in modulating signal frequency, what circuit is used between the modulating signal and the phase modulator?
Alow-pass filter
Bhigh-pass filter
Cphase shifter
Dbandpass filter
#311
With phase modulation, peak phase deviation is called ___________
Amodulation index
Bfrequency deviation
Cphase deviation
Dinstantaneous phase
#312
The unmodulated carrier is a single-frequency sinusoid commonly called _______
Aunrest frequency
Brest frequency
Cfrequency modulated frequency
Dcarrier frequency
#313
It is a circuit in which a carrier is varied in such a way that its instantaneous phase is proportional to the integral of the modulating signal
Aphase modulator
Bphase deviator
Camplitude deviator
Dfrequency modulator
#314
He mathematically proved that for a given modulating signal frequency, a frequency modulated wave cannot be accomodated in a narrower bandwidth than an amplitude modulated wave
AR.C. Alpine
BE.H. Armstrong
CJ.R. Carson
DJ.J. Thomson
#315
Low index FM systems are also known as ________
Awideband FM
Bnarrowband FM
Ccommercial FM
Dmedium FM
#316
For high-index signal, a method of determining the bandwidth is called ________ approach
Aquasi-stationary
Bquasi-movement
Cquasi-deviation
Dany of these
#317
The primary disadvantage of FM is its
Ahigher cost and complexity
Bexcessive use of spectrum space
Cnoise susceptibility
Dlower efficiency
#318
It is the worst-case modulation index and is equal to the maximum peak frequency deviation divided by the maximum modulating-signal frequency
Apeak phase deviation
Bfrequency deviation
Cdeviation ratio
Dsignal-to-noise ratio
#319
The highest side frequencies from one channel are allowed to spill over into adjacent channels producing an interference known as _________
Aco-channel interference
Badjacent channel interference
Csplatter
Dovermodulation
#320
The primary disadvantage of direct PM
Arelatively unstable LC oscillators must be used to produce carrier frequency which prohibits using crystal oscillators
Brelatively high-frequency deviations and modulation indices are easily obtained due to the fact that the oscillators are inherently unstable
Ccrystal oscillators are inherently stable and therefore more difficult for them to achieve high phase deviations and modulation indices
Dcarrier oscillator is isolated from the actual modulator circuit and therefore can be stable source

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