Electrical Engineering · Question Bank

Communications

408 questions · page 19 of 21. Answer in your head first, then check the solution.

📘 EE Mock Board Exam
#361
What is the reason for using pre-emphasis?
Aincrease amplitude
Breduce carrier shift
Camplify RF signal
Dreduce noise reception
#362
What special circuits are used in a squelch system that can follow changing noise levels?
Anoise amplifiers
Brectifier
Cdc amplifier
Dany of these
#363
Why might FM be better than AM for mobile ________
Abetter coverage
Bnot affected by solar cycles
Creduce flutter
Dnot absorbed by ionosphere
#364
What is another name for reactance-tube modulator?
ACrosby
BFoster-Seeley
CRound Travis
DMessier
#365
The ff are significant circuits in the AFC system except:
Acrystal
Bmixer
CIF
Dfilter
#366
Besides the reactance-tube modulator, what is another method of producing direct FM?
AArmstrong modulator
Bvoltage variable capacitor
Cimpedance modulator
Dslug inductor
#367
What is the advantage of PM?
Acan use crystal oscillator
Buses more multistage
Cless selective fading
Dsimplicity
#368
What was the first Broadcast FM system called?
AArc transmitter
BSpark-gap transmitter
CArmstrong
Dcrystal set
#369
Why are limiters used in FM transmitters?
Aclip noise peaks
Bprevent overdrive of discriminators
Cprevent overdeviation
Dany of these
#370
Why are limiters used in FM receivers?
Aprovide better noise performance
Bclip noise peaks
Cprevent overdrive of discriminator
Dany of these
#371
What signals might feed INTO an FM broadcast station audio control console?
Amicrophones
Bturntables
Cremote lines
Dany of these
#372
What signals might feed OUT of an FM broadcast station audio control console?
Amonitor speakers
Btelephone lines
Cprogram signals
Dcarrier signal
#373
What method of measuring FM transmitter power uses a dummy antenna?
Aindirect
Bdirect
Cfeed
Dshunt
#374
What accuracy must meter in the output stage of an FM transmitter have?
A10%
B5%
C2%
D20%
#375
What is the frequency tolerance of Educational FM stations?
A25 kHz
B75 kHz
C2 kHz
D5 kHz
#376
What information can be obtained from FM broadcast station frequency monitors?
Afrequency
Bdeviation
Cwarning light or sound
Dany of these
#377
What is indicated if the frequency meter deviates when FM is applied?
Adistortion of emission in transmitter or monitor
Bdeviation of frequency of the carrier
Cphase shifting of the carrier
Dnone of these
#378
How often must equipment performance test be made on an FM broadcast transmitter systems?
Aweekly
Byearly
Cmonthly
Ddaily
#379
What antenna polarization is used with public safety service equipment and FM broadcast?
Avertical
Bhorizontal
Ccircular
Dhorizontal or circular
#380
A class-C RF amplifier is collector amplitude modulated and its average dc level collector current does not change. This means
Aa normal condition
Bexcessive drive to the base
Cinsufficient drive to the base
Dinsufficient audio modulation

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