Electrical Eng. · Question Bank
Communications
408 questions · page 1 of 21. Answer in your head first, then check the solution.
#1
This is the system so far referred to as "SSB" in which the carrier is supressed by at least 45 dB in the transmitter.
#2
Random interference to transmitted signals is called
AAdjacent channel overlap
BCross talk
CGarbage - in - Garbage - out
DNoise
#3
A diagram which shows the relationship between RF signal phase and maximum bunching of the electron beam in velocity-modulated devices.
ASmith chart
BVenn Diagram
CS-parameter Diagram
DApplegate Diagram
#4
An adjustable resonant cavity calibrated in frequency and which undergoes some power absorption at resonance.
AFrequency Meter
BCavity resonator
CFerrite isolator
DAuto Coupler
#5
The big breakthrough in electronic communications came with the invention of the _____ in 1844.
ATransistor
BPhonograph
CTelegraph
DTelephone
#6
Which came first, the invention of the telephone or the invention of the phonograph?
ATelephone
BPhonograph
CEither
DNeither
#7
What is a device such as the microphone and headset sometimes called?
AReceiver
BTransmission medium
CConverter
DReproducer
#8
Best describe as an amplifier used in radio telephony.
AMagnifier
BClass B
CClass C
DClass A
#9
Where is ISB primarily used?
ATelephone and telegraph communications
BTelemetry
CFM broadcast
DRadar
#10
What is a major problem with very high frequency oscillator?
Alow sensitivity
Bpoor frequency stability
Cpoor image rejection
Dno power stability
#11
What happens to the spectrum of repetitive pulse as the pulse width decreases?
Amore harmonics of the same phase
Bless harmonics of the same phase
Cremain constant
Ddecreases
#12
Keyed AGC is AGC that:
AWorks only on Morse code
BIs activated when keyed by the transmitting signal
CIs used is TV receivers so that transmitted picture brightness does not affect the AGC
DIs used in color TV receivers so that the transmitted color has no effect on the AGC
#13
What is the main disadvantage of a single-tube transmitter
AFrequency instability
BLow gain
CHigh resistivity
DHigh attenuation
#14
What type of coupling discriminates against harmonic transmission?
ACapacitive
BDirect
CTransformer
DInductive
#15
What type of circuit reduces even-order harmonics?
APush-pull
BClass A
CArmstrong circuit
DDemodulator
#16
What is another name for an AF volume control?
#17
What method can be used to invert speech?
AFrequency multiplier
BInverter
CAGC
DFrequency translation
#18
In SSB, voice compression is better in the AF or RF section?
#19
Which of the following services would use crystal local oscillators?
AAM
BFM
CAircraft
DShortwave listeners
#20
What causes audio signals to be distorted in the receiver?
AInterference
BGain
CHarmonics
DAmplitude
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