Electrical Engineering · Question Bank

Communications

408 questions · page 3 of 21. Answer in your head first, then check the solution.

📘 EE Mock Board Exam
#41
At what power level does a 1 kHz tone cause zero interference (144 weighted)?
A90 dB
B90 dBm
C-90 dB
D-90 dBm
#42
Reference noise is ___________.
Aa 1000 Hz, -90 dBm tone
Ba noise that creates the same interfering effect as a 1000 Hz, -90 dBm tone
Ca noise that creates zero dBrn in a voice channel
Dall except a 1000 Hz, -90 dBm tone
#43
A practical dBrn measurement will almost always in a ____________ number.
Apositive
Bnegative
Cimaginary
Dfractional
#44
What is the reference level for noise measurement, F1A weighted?
A-90 dBm
B-82 dBm
C-67 dBm
D-85 dBm
#45
What is the reference tone level for dBa?
A-90 dBm
B-82 dBm
C-67 dBm
D-85 dBm
#46
Indicate the false statement.
AThe noise generated in a resistance or the resistive component of any impedance is random
BRandom noise power is proportional to the bandwidth over which it is measured
CA random voltage across the resistor does not exist
DAll formula referring to a random noise are applicable only to the value of such noise
#47
Indicate the false statement. Noise figure is defined as
Athe ratio of the S/N power supplied at the input terminal of a receiver or amplifier to the S/N power supplied to the output or load resistor
Bnoise factor expressed in decibels
Can unwanted form of energy tending to interfere with the proper and easy reception and reproduction of wanted signals
DS/N of an ideal system divided by S/N at the output of the receiver or amplifier under test, both working at the same temperature over the same bandwidth and fed from the same source
#48
Noise at the input to a receiver can be as high as several
Amicrovolts
Bmillivolts
Cvolts
Dkilovolts
#49
Noise that occurs via capacitive or inductive coupling in a cable
ACrosstalk
BQuantizing noise
CReference noise
DTone interference
#50
Sources of impulse noise induced in communication channels.
AErroneous digital coding bit caused by an error on a transmission facility
BTransients due to relay operation
CCrosstalk from dc signaling systems
DAll of these
#51
Crosstalks due to incomplete suppression of sidebands or to intermodulation of two or more frequency-multiplexed channels which are unintelligible is classified as
Aimpulse noise
Bthermal noise
Cquantizing noise
Dmiscellaneous noise
#52
The total noise power present in a 1-Hz bandwidth.
ANoise density
BNoise figure
CNoise limit
DNoise intensity
#53
What noise type is observable between 8 MHz to somewhat above 1.43 GHz or up to 1.5 GHz?
ASolar noise
BSpace noise
CGalactic noise
DCosmic noise
#54
Flicker noise is a poorly understood noise which may be completely ignored about above _________
A100 Hz
B200 Hz
C400 Hz
D500 Hz
#55
What noise is a transient short duration disturbance distributed essentially uniformly over the useful passband of a transmission system?
AFlicker noise
BTransit-time noise
CShot noise
DImpulse noise
#56
Phase jitter occurs at what frequency?
Aless than 300 Hz
Bmore than 300 Hz
Cmore than 400 Hz
Dmore than 300 Hz but less than 400 Hz
#57
________ is a multi-channel capacity that is between 1.544 Mbps and 45 Mbps according to the US standards (2.048 Mbps and 34 Mbps according to European)
AWideband
BBaseband
CNarrowband
DBroadband
#58
He hypothesized the existence of magnetic field around a current carrying conductor
AMichael Faraday
BAndre Ampere
CNikola Tesla
DCarl Gauss
#59
A quasi-stationary noise with a finite power spectrum with a finite number of small bands of zero energy dispersed throughout a continous spectrum
Awhite noise
Borange noise
Cviolet noise
Dblue noise
#60
It is also known as differentiated white noise or violet noise
Apink noise
Bgreen noise
Cblue noise
Dpurple noise

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