Electronic Noise

7/26/2019 Electronic Noise

1/100

1. Examples of intrinsic Noise are ____.

a. Thermal noise from resistorsb. Noise generated by op amps

c. Capacitive coupling of digital signals

d. Both a and b are correct

D


2/100

. ! common amplifier noise modelcontains ___.

a. !n input and output noise voltage source.b. !n input current noise source" and voltage noise source.

c. !n e#uivalent input resistance.

d. !n input and output e#uivalent resistance

B


3/100

$. %hich standard is utili&ed in intermodulationnoise rates on 'C( audio channels)

!. CC*T +ec. ,.1-1

B. CC*T +ec. ,.1

C. CC*T +ec. ,.1/0

D. CC*T +ec. ,.1/0

B


4/100

.+eference temperature use in noiseanalysis !. - 2

B. -0 2

C. /0 2

D. $00 2

C


5/100

-.Thermal Noise is ____.

a. ,enerated by resistors

b. ,enerated by semiconductor 3unctions

c. Dependent on current flo4

d. Dominant at lo4 fre#uencies.

!


6/100

5. The 16f noise region occurs at ____.

a. 7o4 fre#uency

b. (edium fre#uency

C. 8igh fre#uency

D. No fre#uency

!


7/100

. 8o4 do you convert pea9:to:pea9 torms)

a. Noise_pp; 5 x


8/100

>. ?oltage noise spectral density hasunits of ___.

a. n?68&

b. n?6!

c. n?6rt8&

d. p!68&

!


9/100

/.8o4 do you find the total noise for t4o series sources


10/100

10. %hat is the difference bet4een +(Aand standard deviation)

a. Atandard deviation eliminates the average value" but +(A includes it.

b. There is no difference.

c. +(A ; 5 x Atandard Deviation

d. * dont 9no4

!


11/100

11. %hat is the difference bet4een +(Aand standard deviation) !. Non:intrinsic figure

B. Noise improvement factor

C. Narro4 intermediate fre#uency

D. Noise interference figure

B


12/100

1. *s the interference coming fromother communications channels) !. itter

B. Crosstal9

C. +*

D. E(*

B


13/100

1$. *ndicate the noise 4hose sources are incategory different from that of the other three)

!. Aolar noise

B. Cosmic noise

C. !tmospheric noise

D. ,alactic noise

C


14/100

1. %hich of the follo4ing is not asource of industrial noise) !. !utomobile ignition

B. Aun

C. Electric (otors

D. 7ea9age from high voltage line

B


15/100

1-. The total noise po4er present in a 1 8& band4idth a. Noise density

b. Noise figure

c. Noise limit

d. Noise intensity

!


16/100

15. _____ Noise is the most prevalent noise found in urban areas and isnormally caused by the arc discharge from automobile or aircraftignition systems" induction motors" s4itching gears" high voltage linesand the li9e. a. *ndustrial

b. ohnson

c. lic9er

d. (ixer

!


17/100

1. The follo4ing characteristics ofnoise except a. Fn4anted energy

b. 'redictable in character

c. 'resent in the channel

d. Due to any cause

B


18/100

1>. The value of a resistor creating thermal noise isdoubled. The noise po4er generated is therefore

a. 8alved

b. Guadrupled

c. Doubled

d. Fnchanged

D


19/100

1/. Aignal attenuation can be correctedby a. iltering

b. (odulation

c. E#uali&ation

d. !mplification

D


20/100

0. Distortion in a 4aveform can becorrected by a. iltering

b. (odulation

c. E#uali&ation

d. !mplification

C


21/100

1. The transmitter techni#ue adopted to reducethe noise effect of the preceding #uestion is called

!. noise mas9ing

B. anitnoise

C. noise 9illing

D. preemphasis

D


22/100

. %here is the noise generated that primarily determines thesignal:to:noise ratio in a ?8


23/100

$. *ndustrial noise fre#uency isbet4een _____. !. 0 to 10 28&

B. 150 (8& to 00 (8&

C. 1- to 150 (8&

D. 00 to $000 (8&

C


24/100

. External noise fields are measured interms of _______. !. rms values

B. dc values

C. average values

D. pea9 values

D


25/100

-. *ndicate the false statement.

!. 8 mixer are generally noisier than 8 amplifiers.

B. *mpulse noise voltage is dependent on band4idth

C. Thermal noise is independent of the fre#uency at 4hich is measured.

D. *ndustrial noise is usually of the impulse type.

B


26/100

5. Hne of the follo4ing is not a useful #uantityfor comparing the noise performance receivers.

!. *nput noise voltage

B. E#uivalent noise resistance

C. Noise temperature

D. Noise figure.

!


27/100

. %hich of the follo4ing is not asource of external noise) !. Thermal agitation

B. !uto ignition

C. The sun

D. luorescent lights

!


28/100

>. Noise at the input to the receivercan be as high as several !. microvolts

B. milivolts

C. volts

D. 9ilo volts

!


29/100

/. %hich of the follo4ing types of noisebecomes of great importance at fre#uencies)

!. Ahot noise

B. +andom noise

C. *mpulse noise

D. Transit:time noise

D


30/100

$0. The s#uare of the thermal noise voltagegenerated by a resistor is proportional to

!. its resistance

B. its temperature

C. the band4idth over 4hich it is measured

D. !ll of the above

D


31/100

$1. Noise consisting of irregular pulses of shortduration and relatively high amplitude"

!. Guanti&ing noise

B. Tone interference

C. *mpulse noise

D. Cross tal9

C


32/100

$. Crosstal9 due to incomplete suppression of sidebandsor to intermodulation of t4o or more fre#uency:multiplexed channels 4hich is unintelligible is classified as !. *mpulse noise

B. Thermal noise

C. Guanti&ing noise

D. (iscellaneous noise

D


33/100

$$. %hich of the follo4ing is not a 4ayof minimi&ing if not eliminating noise) !. Fse redundancy

B. *ncrease transmitted po4er

C. +educe signaling rate

D. *ncrease channel band4idth

D


34/100

$. %hat do you call the noise comingfrom the sun and stars) a. Blac9:body noise

b. Apace noise

c. ,alactic noise

d. !ll of these

B


35/100

$-. %hat is the primary cause ofatmospheric noise) a. Thunderstorm

b. 7ightning

c. Thunderstorm and lightning

d. %eather condition

B


36/100

$5. !ny un4anted form of energy that tends tointerfere 4ith the 4anted signal is called

a. Noise

b. Apectrum

c. +adiation

d. !bsorption

!


37/100

$. Noise from distant panels" stars" galaxiesand other celestial ob3ects are called

a. Cosmic

b. Extraterrestrial

c. ,alactic

d. Blac9 body

B


38/100

$>. *ndicate 4hich one of the follo4ing typesof noise does not occur in transistors

a. Ahot noise

b. lic9er noise

c. 'artition noise

d. +esistance noise

C


39/100

$/. Noise that is due to the random and rapid motionof the charge carriers inside a resistive component.

a. ohnson

b. Thermal !gitation

c. %hite

d. !ll of the above

D


40/100

0. Thermal noise is also 9no4n as

a. ,aussian Noise

b. %hite Noise

c. ohnson noise

d. !ll of the above

D


41/100

1. *mpulse Noise is

a. ! function of current

b. ! shot duration pulse

c. Dependent of fre#uency

d. Dependent of temperature

B


42/100

. *t is characteri&ed by high amplitude pea9sof short duration in the total noise spectrum

a. *ntermodulation voice

b. *mpulse noise

c. Dropout

d. 'hase hits

B


43/100

$. Aignal contamination by extraneousor external sources" such as" othertransmitters" po4er lines" andmachinery.

a. Noise

b. Distortion

c. 8armonics

d. *nterference

D


44/100

. (an:made or industrial noise is also9no4n as a. Noise

b. Distortion

c. *nterference

d. Thermal Noise

C


45/100

-. Noise that is caused by naturaldisturbances such as lightning discharge. a. Atatic noise

b. Apace noise

c. !tmospheric noise

d. ! or C

D


46/100

5. %hich statement is true

a. *ndustrial noise is usually of impulse type

b. Distant stars produce atmospheric noise c. !ctive s4itches are sources of man:made noise

d. Atatic noise is due to lightning discharges and other natural electric disturbancethe atmosphere.

B

h h b


47/100

. %hich circuit contributes most tothe noise at the receiver) a. + amplifier

b. (ixer c. Detector

d. 7ocal Hscillator

!

> %hi h f th f ll i i t i t t


48/100

>. %hich of the follo4ing is not an importantcause of distortion in DC signaling

a. line resistance

b. line inductance c. line capacitance

d. all of the above

B

/ Th t f i i d i g


49/100

/. The amount of noise po4er is measured using apsophometric 4eighting net4or9. This unit ofmeasurement is generally used in Europe 4here thestandard reference tone is >00 hert&" 1 pico4att. a. dBa

b. dBm c. dBaH

d. p%p

D

-0 N i d d tl b li ht i


50/100

-0. Noise produced mostly by lightningdischarges in thunderstorms. a. %hite noise

b. *ndustrial noise c. !tmospheric noise

d. Extraterrestrial noise

C

-1 %h t i th it f i f


51/100

-1. %hat is the unit of noise po4er ofpsophometer) !. p%p

B. dBa C. dBm

D. dBrn

!

- ! l g i i f h d g f


52/100

-. ! large emission of hydrogen fromthe sun that affects communications. !. Aolar flare

B. Cosmic disturbance C. Ballistic disturbance

D. Aolar noise

D

-$ Atandard design reference for


53/100

-$. Atandard design reference forenvironmental noise temperature. !. $00 2

B. /0 2 C. $ I

D. 1I

B

- *f band4idth is doubled the signal


54/100

-. *f band4idth is doubled" the signalpo4er is _________. !. not changed

B. #uadrupled C. tripled

D. doubled

!

-- Name one or more sources of noise


55/100

--. Name one or more sources of noisebearing on electronic communications. !. Ateam boiler

B. ,alaxies C. *nternal combustion engine

D. Both B and C

D

-5 The transmitter techni#ue adopted to reduce


56/100

-5. The transmitter techni#ue adopted to reducethe noise effect of the preceding #uestion is called

!. noise mas9ing

B. anitnoise C. noise 9illing

D. preemphasis

D

-. Deemphasis in the receiver in effect atte


57/100

modulating signal components and noise in 4fre#uency range)

!. dc B. lo4

C. intermediate

D. high

D

-> !tmospheric noise or static is not a


58/100

->. !tmospheric noise or static is not agreat problem !. at fre#uencies belo4 0 (8&

B. at fre#uencies belo4 - (8& C. at fre#uencies above $0 (8&

D. at fre#uencies above 1 (8&

C

-/. %hat is the proper procedure for


59/100

-/. %hat is the proper procedure forsuppressing electrical noise in a mobile station)

!. !pply shielding and filtering 4here necessary

B. *nsulate a all plain sheet metal surfaces from each other C. !pply anti:static spray liberally to all nonmetallic

D. *nstall filter capacitors in series 4ith all dc 4iring

!

50. %here is the noise generated that primar


60/100

determines the signal:to:noise ratio in a ?8


61/100

is doubled. The noise po4er generated is the

!. halved B. #uadrupled

C. doubled

D. unchanged

D

5 *ndicate the false statement


62/100

5. *ndicate the false statement.

!. 8 mixer are generally noisier than 8 amplifiers.

B. *mpulse noise voltage is dependent on band4idth C. Thermal noise is independent of the fre#uency at 4hich is measured.

D. *ndustrial noise is usually of the impulse type.

B

5$. Hne of the follo4ing is not a useful #uantity


63/100

g # yfor comparing the noise performance receivers.


B. E#uivalent noise resistance C. Noise temperature

D. Noise figure.

!

5. (ost internal noise comes from


64/100

5. (ost internal noise comes from

!. Ahot noise

B. Transit:time noise C. Thermal agitation

D. A9in effect

C

5-. %hich of the follo4ing is not a


65/100

5-. %hich of the follo4ing is not asource of external noise) !. Thermal agitation

B. !uto ignition C. The sun

D. luorescent lights

!

55. Noise can be reduced by


66/100

55. Noise can be reduced by

!. 4idening the band4idth

B. narro4ing the band4idth C. increasing temperature

D. increasing transistor current levels

B

5. Noise at the input to the receiver


67/100

pcan be as high as several !. microvolts

B. milivolts C. volts

D. 9ilo volts

B

5>. Noise at the input to the receiver


68/100

pcan be as high as several !. microvolts

B. milivolts C. volts

D. 9ilo volts

B

5/. %hich of the follo4ing types of noise


69/100

becomes of great importance at fre#uencies)

!. Ahot noise

B. +andom noise C. *mpulse noise

D. Transit:time noise

D

0. Hne of the follo4ing is not useful for


70/100

comparing the noise performance of receivers


B. E#uivalent noise resistance C. Noise temperature

D. Noise figure

!

1. *ndicate the noise 4hose source is in


71/100

a category different from that !. Aolar noise

B. Cosmic noise C. !tmospheric noise

D. ,alactic noise

C

. The most common unit of noise


72/100

measurement in 4hite noise voltage testing

!. N'+

B. dBrn C. dB%

D. dBm

!

$. %hat is the ma3or cause of


73/100

atmospheric or static noise) !. (eteor sho4ers

B. Aunspots C. !irplanes

D. Thunderstorms

D

. Bac9ground noise is the same as the


74/100

follo4ing EJCE'T a. *mpulse noise

b. Thermal noise c. %hite noise

d. ,aussian noise

!

-. Noise is caused by the thermal


75/100

agitation of electrons in resistance a. %hite noise

b. Thermal noise c. ohnsons noise

d. !ll of these

D

5. NoExtra:terrestrial noise is


76/100

observable at fre#uencies from a. 0 to 0 28&

b. !bove ,8& c. > (8& to 1.$ ,8&

d. - to > ,8&

C

. %hat signal:to:noise ratio is re#uired


77/100

for satisfactory telephone services) a. -0 dB

b. $0 dB c. 0 dB

d. 0 dB

!

>. %hich does not affect noise in a


78/100

channel) a. None of these

b. Band4idth c. Temperature

d. Guanti&ing level

D

/. +eference noise temperature)


79/100

a. 0 deg

b. $0 deg C

c. /0 2elvin

d. - deg C

C

>0. %hat does the noise 4eighing curveh )


80/100

sho4) a. Noise signals measured 4ith a 1 handsets

b. 'o4er levels of noise found in carrier systems

c. The interfering effect of other fre#uencies in a voice channel compared 4ith a rfre#uency of one 9ilohert&

d. *nterfering effects of signals compared 4ith a $:28& tone

C

>1. Express the ratio in decibels of noiseti -0 i t 10 tt


81/100

po4er ratio -0 is to 10 4atts. a. dB

b. 1 dB

c. 1 dB

d. $.- dB

!

>. %hat do you call the noise comingf th d t )


82/100

from the sun and stars) a. Blac9:body noise

b. Apace noise

c. ,alactic noise

d. !ll of these

B

>$. %hat is the primary cause oft h i i )


83/100

atmospheric noise) a. Thunderstorm

b. 7ightning

c. Thunderstorm and lightning

d. %eather condition

B

>. The solar cycle repeats the period if greatelectrical disturbance approximately every


84/100

electrical disturbance approximately every

a. 11 years

b. 10 years

c. / years

d. > years

!

>-. ! current change that is e#ual to t4ice itsoriginal value 4ill correspond to a change of


85/100

original value 4ill correspond to a change of

a. $ dB

b. / dB

c. 10 dB

d. 5 dB

D

>5. %hat does a po4er difference of $dB mean)


86/100

dB mean) a. $ dB

b. / dB

c. 10 dB

d. 5 dB

D

>. %hat does a po4er difference of $dB mean)


87/100

dB mean) a. ! loss of one third of the po4er

b. ! loss of one:half of the po4er

c. ! loss of $ 4atts of po4er

d. No significant change

B

>>. ! gain of 50 dB is the same as a gain of


88/100

a. 10 volts6volt

b. 100 volts6volt

c. 1000 volts6volt

d. 10"000 volts6volt

C

>/. ! net4or9 has a loss of 0 dB. %hatpo4er ratio corresponds to this loss


89/100

po4er ratio corresponds to this loss a. 0.01

b. 0.1

c. 10

d. 100

!

/0. The noise figure of a totallynoiseless device is


90/100

noiseless device is a. Fnity

b. *nfinity

c. Lero

d. 100

!

/1. ! net4or9 has a po4er gain of $ dB. *f theinput po4er is 100 4atts" the output po4er is


91/100

p p " p p

a. -0 4atts

b. -- 4atts

c. 50 4atts

d. 5 4atts

!

/. %hich of the follo4ing types of noise becomesof great importance at high fre#uencies)


92/100

a. Ahot

b. +andom

c. *mpulse

d. Transmit time

D

/$. %hat is the gain" in dB" if the outputto input ratio is 1000


93/100

to input ratio is 1000. a. 0

b. $0

c. 0

d. 10

B

/. ! theoretical antenna has a gain of1dB *ts gain in nepers is


94/100

1dB. *ts gain in nepers is a. >.5>5

b. 0.11-1

c. 5.>5>

d. 0.-111

B

/-. %hat is the e#uivalent output of a circuitin dBm" if it has an output of 10 4atts)


95/100

a. 10 dBm

b. $0 dBm

c. 0 dBm

d. 0 dBm

D

/5. Noise from distant panels" stars" galaxiesand other celestial ob3ects are called


96/100

a. Cosmic

b. Extraterrestrial

c. ,alactic

d. Blac9 body

B

/. *n a communication system" noise isli9ely to affect the signal


97/100

li9ely to affect the signal a. !t the transmitter

b. *n the channel

c. *n the information source

d. !t the destination

B

/>. The noise po4er generated by aresistor is proportional to


98/100

es sto s p opo t o al to a. Temperature

b. Band4idth

c. a and b

d. NHT!

C

//. Thermal noise is also 9no4n as


99/100

a. ,aussian Noise

b. %hite Noise

c. ohnson noise

d. !ll of the above

D

100. *ndustrial noise extends up to 4hatfre#uency)


100/100

# y a. -00 (8&

b. -00 ,8&

c. -00 T8&

d. -00 28&

!

Electronic Noise

Documents

Transcript of Electronic Noise