Quiz
Wireless Networking Quiz
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Fragen in diesem Quiz (90)
1There is/will be no perfect network in terms of features such as coverage, mobility, transmission rate, smartness, cost. Tradeoffs exist.
- ARichtig
- BFalsch
2Types of Wireless Networks in order of size:
- APAN LAN MAN WLAN
- BPAN WLAN MAN LAN
3Satellite Networks are used to transmit data over very long distances through:
- AA repeater: located in the satellite itself.
- BData is transmitted from one earth station to another
- CTransmission is approx 250 mS
- DLine of Sight Problem
- ESatellites are bloothtooth technology.
4Access point relays data signal between all of the devices in the network
- ARichtig
- BFalsch
5Each computer on a WLAN has a NIC card with built in antenna
- ARichtig
- BFalsch
65 Areas of RF regulation. Choose
- AFrequency
- BBandwidth
- CMAX power of intentional radiator IR
- DMax equivalent isotropically radiated power EIRP
- EIndoor/outdoor usage
- FSpectrum Sharing Rules
- GPuta
7In the Hierarchical Network model what are the three layers and their typical functions:
- ACore layer
: Backbone, transport data reliably and quickly - BDistribution layer: Routing,
filtering, WAN access - CAccess layer: Switching, separating collision domains
- DData layer: separating, data, domains
- ACore layer
8What are the fundamental elements of cellular systems architecture?
- ACore Network, Radio Access Network (RAN), User Equipment, Radio Interface (also called Air Interface or Wireless Interface) -this is a logical element.
- BDAN, CPU Network, User Equipment
- CEMR, Core Network, Radio Access Network
9Components of a Wave:
- AAmplitude is the height, force, or power of the wave, measured In Volts
- BFrequency Number of waves generated per second, measured in HZ
- CWavelength Distance between similar points on back-to-
back waves. Typically measured from peak to peak - DHertz - the distance between two waves in corresponding order of height.
10[blank_start]Phase[blank_end] is the relationship between two waves with the [blank_start]same[blank_end] frequency. Measured in [blank_start]degrees[blank_end].
- APhase
- Bsame
- Cdegrees
11RF signal can represent data by fluctuating or altering its RF
properties- ARichtig
- BFalsch
12What three properties of a signal can be altered to rep data?
- AHeight, Width, Phase
- BWavelength, frequency, Phase
- CPhase, Frequency, Distance
- DAmplitude, Frequency, Phase
13Keying Methods are a Method of manipulating a signal to represent multiple pieces of data. Three types of Keying methods:
- AAmplitude-shift keying (ASK)
- BFrequency-shift keying (FSK)
- CPhase-shift keying (PSK)
- DCurrent State keying (CSK)
14Two techniques used to represent data are: [blank_start]Current[blank_end] state, [blank_start]State[blank_end] transition.
- ACurrent
- BState
15[blank_start]Current State:[blank_end] Current [blank_start]value[blank_end] of the signal is used to distinguish between 0s and 1s. Current value or level at a specific time
- Avalue
- BCurrent State:
16[blank_start]State Transition[blank_end]: A change or transition of the signal is used to distinguish between
0s and 1s. Presence of a change or lack of presence of a change determines 0 or 1.- AState Transition
17 Amplitude-Shift Keying (ASK):
- ACurrent State Technique
- BOne level represents 0, different level represents 1
- CAmplitude or height of a signal represents the binary data
- DState Transition Technique
18 Frequency-Shift Keying (FSK)
- AFrequency of the wave is varied to represent the binary data
- BBoth Current state technique and State Transition technique
- CCurrent state technique
- DOne frequency represents 0 and different frequency represents 1
- EOne amplitude represents 0 and different amplitude represents 1
19 Phase-Shift Keying (PSK)
- APhase of the wave is varied to represent the binary data
- BState transition technique
- CCurrent State technique
- DChange of phase represents 0 or 1
- ELack of phase change represents 1 or 0
- Fcommonly used
20 Multiple Phase-Shift Keying (M- PSK)
- ACan encode multiple bits per symbol
- BUses four phases, each of which is capable of representing two binary values (00, 01, 10, or 11)
- CUses four phases, each of which is capable of representing four binary values (00, 01, 10, or 11)
21 What is a Radio Frequency signal?
- AElectromagnetic wave incldues Radio, micro, gamma ray xray etc.
- BOperates in the electromagnetic spectrum
- Cgenerated by radiating AC signal out of an antenna
- Dgenerated by radiating DC signal out of an antenna
22In RF communication RF [blank_start]transmitters[blank_end] generate waves and RF [blank_start]receivers[blank_end] accept waves.
- Atransmitters
- Breceivers
23Frequency and wavelength actually represent the same characteristics, just different representations
- ARichtig
- BFalsch
24Phase is relevant only when you can compare multiple signals
- ARichtig
- BFalsch
25[blank_start]Transmit[blank_end] amplitude = [blank_start]Initial[blank_end] amplitude that leaves the radio transmitter. [blank_start]Receive[blank_end] amplitude = Received signal strength.
- ATransmit
- BReceive
- CInitial
26Frequency is defined as and measured in?
- AThe number of times a specified event occurs within a specified time period. In RF, measured as the number of alternation of wave over a 1 second period. Measured in Hz, KL, MHz, Km
- BThe number of times a specified event occurs within a specified time period. In RF, measured as the number of alternation of wave over a 1 second period. Measured in Hz, KHz, MHz, GHz
- CThe number of times a specified event occurs within an unspecified time period. In RF, measured as the number of alternation of wave over a 1 second period. Measured in Hz, KHz, MHz, GHz
27Wavelength is
- ALower frequency means smaller wavelength
- BDistance between two successive points of a wave pattern
- CRepresented by the Greek symbol λ
- DHigher frequency means smaller wavelength
28Which of the following regarding RF wavelength is false?
- AHigh frequency can hold more data
- Bhigher freq dies more quickly
- CThere is a relationship between antenna length and freq. Low freq antenna needs to be bigger.
- DLow frequency holds more data and is the preferred method of data transfer
29There is an [blank_start]inverse[blank_end] relationship between [blank_start]wavelength[blank_end] and frequency. Three components of this relationship: Frequency (f), measured in [blank_start]hertz[blank_end] (Hz), Wavelength (λ), measured in [blank_start]meters[blank_end] (m), Speed of light (c) 3x108 m/sec
- Ainverse
- Bwavelength
- Chertz
- Dmeters
30Which of the following is false about Phase or The relationship between two or more signals that share the same frequency?
- AIn Phase = two waves with the same peaks in exact alignment
- BMeasure in distance, time, or degrees
- COut of Phase = two waves with the same peaks but not in same alignment
- DThe relationship between two or more signals that share the same amplitude
31Which of the following are effects of phase on amplitude?
- AWith any other difference in phase, depending upon the amount of phase separation, the resulting signal could increase or decrease
- BTwo in-phase waves (0 degree separation) will combine their amplitude, resulting in a received signal with a greater signal strength
- COut of phase signals always result in a lower signal strength
- DTwo waves 180 degrees out of phase will cancel each other out, resulting in an effective received signal strength of null
32 [blank_start]Wave Propagation[blank_end] : The [blank_start]movement[blank_end] or motion of RF waves as they pass through the [blank_start]medium[blank_end] (the air). May be [blank_start]impeded[blank_end] or completely stopped by [blank_start]materials[blank_end] in the path of the signal.
- AWave Propagation
- Bmedium
- Cmovement
- Dimpeded
- Ematerials
33[blank_start]Absorption[blank_end] = When an RF signal is not allowed to pass through an object, is not [blank_start]reflected[blank_end] by it and is not [blank_start]diffracted[blank_end] around it, the signal will be absorbed to some extent by the object.
- AAbsorption
- Breflected
- Cdiffracted
34Absorption is:
- AMost common RF behavior
- BMost materials will absorb some amount of an RF sign
- CDenser materials will absorb more RF signal
- DA leading cause of attenuation
- EDirectly effects the amplitude of the wave
- FDirectly effects the phase and amplitude of the wave
35[blank_start]Reflection[blank_end] = When an RF signal strikes an object that does not [blank_start]absorb[blank_end] the signal and does not cause the signal to be [blank_start]diffracted[blank_end] around the object, the signal is [blank_start]reflected[blank_end] by the object.
- AReflection
- Babsorb
- Cdiffracted
- Dreflected
36Reflection is:
- ACause of multipath signal
- Bdoes not absorb the signal
- Ccauses the signal to be diffracted
37[blank_start]Sky wave[blank_end] reflection can occur in frequencies below 1 GHz (large wavelengths). Microwave reflection occur between [blank_start]1 GHz[blank_end] and [blank_start]300 GHz[blank_end] (smaller wavelengths)
- ASky wave
- B1 GHz
- C300 GHz
38[blank_start]Scattering[blank_end] = Multiple reflections, Occurs when the wavelength is [blank_start]larger[blank_end] than pieces of the medium the signal is hitting. Can occur as a wave moves through an object, reflecting off minute particles with the medium. Can also occur when a wave encounters an [blank_start]uneven[blank_end] [blank_start]surface[blank_end]
- AScattering
- Blarger
- Cuneven
- Dsurface
39Three most common causes of Refraction
- AWater vapor
- BWater density
- CChanges in air temperature
- DChanges in air pressure
- ECharcoal diffusion
40[blank_start]Refraction[blank_end] = The bending of an RF signal as it passes through a medium with a [blank_start]different density[blank_end]. Most commonly occurs due to atmospheric conditions.
- ARefraction
- Bdifferent density
41 [blank_start]Diffraction[blank_end] = The bending of an RF signal around an object. It is the bending and spreading of an RF signal when it encounters an [blank_start]obstruction[blank_end]. Typically caused by a partial blockage of the RF signal. Sitting directly behind the obstruction is an area known as the [blank_start]RF shadow[blank_end]
- ADiffraction
- Bobstruction
- CRF shadow
42What are three forms of propagation related attenuation?
- ACable
- BLightning arrestor
- CAbsorption
- DDistance
- ENegative effects of multipath
43What are three forms of CIRCUITRY related attenuation?
- ARepeaters
- BImpedance mismatch
- CCable
- DAmplifiers
- ELightning arrestors
- FConnectors
- GSignal attenuators
44[blank_start]Free Space Path Loss[blank_end] (FSPL) Attenuation of a signal as it travels. Caused by a [blank_start]broadening[blank_end] of the wave as an RF signal propagates (beam [blank_start]divergence[blank_end]). No external impedance required. Loss of signal strength is [blank_start]logarithmic[blank_end], not [blank_start]linear[blank_end].
- AFree Space Path Loss
- Bbroadening
- Cdivergence
- Dlogarithmic
- Elinear
456 dB rule = [blank_start]doubling[blank_end] the [blank_start]distance[blank_end] will result in a loss of power by 6 dB
- Adoubling
- Bdistance
46Multipath caused by
- ADiffusion
- BAbsorption
- CReflection
- DScattering
- ERefraction
- FDiffraction
47[blank_start]Multipath[blank_end] = two or more paths of a signal arrive at a receiving antenna at the same time or within nanoseconds of each other. [blank_start]Delay Spread[blank_end] = [blank_start]Time[blank_end] differential between multipath signals
- AMultipath
- BDelay Spread
- CTime
48What are the 4 possible results of multipath?
- AUpfade – increased signal strength
- BDownfade – decreased signal strength
- CNulling – signal cancellation
- DData corruption (most common)
- EUnifade - signal changes overtime
49[blank_start]Intersymbol interference[blank_end] - corruption caused by bits overlapping due to delay spread or the difference between multipath signals
- AIntersymbol interference
50What are two types of Gain?
- AActive Gain increase caused by adding additional power. Passive gain increase caused by focusing the RF signal, typically by an antenna
- BAdded gain and Pervasive Gain
- CAmplitude gain caused by increase in amplitude from additional power and Passive gain caused by focusing RF signal.
51We always communicated [blank_start]change[blank_end]. Information is carried by a changing [blank_start]Carrier[blank_end] [blank_start]Signal[blank_end]. Changing of a carrier signal is called [blank_start]modulation[blank_end].
- Achange
- BCarrier
- CSignal
- Dmodulation
52Digital communication is done by ___________ and keying one of the wave properties of _________.
- Afm modulation, wavelength
- Bdigital modulation, carrier signal
- Cdigital modulation, wavelength
- Dcarrier signal, wavelength
53Carrier signals are:
- Ausually pure sine and cosine waves with a fixed amp, free, 360 phase
- BCarrier wave (signal) in its pure (unchanged or unmodulated) form
We change any of the characteristics to convey information - CCannot change Amplitude, Frequency (Wavelength), Phase to convey information
54In digital modulation what are the two technique used to represent data?
- ALast state, change transition
- BCurrent state, state transition
- CCurrent state, final transition
- DState transition, multi state
55[blank_start]Current State[blank_end] - Current value of the [blank_start]signal[blank_end] is used to distinguish between 0s and 1s. Current value or level at a specific time
- ACurrent State
- Bsignal
56[blank_start]State transition[blank_end] - A change or [blank_start]transition[blank_end] of the signal is used to distinguish between
0s and 1s. Presence of a change or lack of presence of a change determines 0 or 1- AState transition
- Btransition
57In amplitude shift keying (ASK related to digital modulation)
- AAmplitude or height of a signal represents the binary data
- BCurrent state technique
- COne level represents 0, different level reps 1
- DState Transition technique
58What is correct about azimuth charts?
- AH-plane = top-down view, E-plane = side view
- BOuter ring usually represents strongest signal
- CInner ring usually represents strongest signalIs
- DIs linear
- Eshows radiation patterns, is logarithmic, and in dB
59What are the components of RF communication?
- ATransmitter
- BAntenna
- CIntentional Radiatior (IR)
- DEquivalent Isotropically Radiated Power (EIRP)
60[blank_start]Data sent[blank_end] [blank_start]Transmitter[blank_end] [blank_start]Antenna cable[blank_end] [blank_start]Intentional Radiator[blank_end] [blank_start]EIRP[blank_end] [blank_start]Radio Waves[blank_end] [blank_start]Antenna[blank_end] Antenna cable [blank_start]Receiver Data Received[blank_end]
- AData sent
- BTransmitter
- CAntenna cable
- DIntentional Radiator
- EEIRP
- FRadio Waves
- GAntenna
- HReceiver Data Received
61What is a transmitter?
- AInitial component in the creation of a wireless signal
- BReceives data from the system and begins RF communication
- CEncodes the data and modulates AC signal
- DSends modulated signal to antenna
- EDetermines the power/amplitude of the signal
- FSends unmodulated signal to antenna
- GReceives data from the system and ends RF communication
62What does the Antenna do?
- AInterface between electrical and EM signals
- BRadiates the RF waves into the air (Tx function)
- CCaptures RF waves from air, passes the AC signal to the receiver (Rx
function) - DActs as a bi-directional passive amplifier
- EFocuses the RF beam
- FTransmitting and receiving functions of an antenna is reciprocal as long as it's same radiation shape
63[blank_start]Isotropic Radiator[blank_end] A point source the radiates equally in all directions.
- AIsotropic Radiator
64[blank_start]Receiver[blank_end]: Final component in wireless signaling. Converts (decodes) carrier signal into 1’s and 0’s. Tries to mitigate the effect of [blank_start]errors[blank_end] in the signal. Deals with very small signal level. Passes the data to the computer to be processed. Removes [blank_start]carrier signal[blank_end].
- Acarrier signal
- BReceiver
- Cerrors
65[blank_start]Intentional Radiator[blank_end] A device that intentionally emits RF energy by radiation or induction. Regulatory bodies (governments) regulate the maximum IR power to prevent [blank_start]cancellation[blank_end] of signals. The amount of power being sent into the antenna for transmission onto the medium
- AIntentional Radiator
- Bcancellation
66Equivalent Isotropically Radiated Power (EIRP) The [blank_start]highest[blank_end] RF signal [blank_start]strength[blank_end] that is radiated by a specific antenna. The maximum effective focused signal strength radiated from an antenna. Regulatory bodies (governments) regulate the maximum EIRP just like the IR. Amount of power the total system places on the medium. [blank_start]Shape[blank_end] of the [blank_start]radiation beam[blank_end] is a major factor.
- Ahighest
- BShape
- Cradiation beam
- Dstrength
67W mW and dBm are absolute measures of power. dB, dBi and dBd are Relative measures.
- ARichtig
- BFalsch
68If power of sine wave is 5V what is the corresponding power?
- A25 W
- B10 W
- C27 W
- D5 W
69dBi is power located at the [blank_start]IR[blank_end]. dBd is power located at [blank_start]EIRP[blank_end]. dBm is an absolute measure of power.
- AIR
- BEIRP
70Power Calculation:
- AP = Voltage x Current or P = V^2 x R
- BR = resistance, usually 1
- CP = V^2
71Decibel is used to measure [blank_start]change in signal strength[blank_end] with either gain or loss. Logarithmic scale. decibels = 10 x log10(P1/P2)
- Achange in signal strength
72Decibel Isotropic (dBi): Is a value compared to what an isotropic radiator would generate. Used to express [blank_start]antenna gain[blank_end]. Also phrased as change in power relative to an antenna.
- Aantenna gain
73Milliwatts Decibel Change
0.0001 [blank_start]-40[blank_end]
0.001 -30
[blank_start]0.01[blank_end] -20
0.1 -10
[blank_start]1 0[blank_end]
10 [blank_start]+10[blank_end]
100 +20
1000 +30
10 000 [blank_start]+40[blank_end]
100 000 +50- A-40
- B0.01
- C1 0
- D+10
- E+40
74For every 10 dBi/dBd of gain you multiply signal strength by 10. For every 3 dBi/dBd of gain multiply the signal strength by 2.
- ARichtig
- BFalsch
75The transmit power is 100mW. There is 3 dB loss (cable etc.) and 10 dBi gain from the antenna. What is the power after transmitter? mW and dBm ________ Power at end of cable? _________ Power after the antenna EIRP? _________
- A10mW 20dBm, 50mW 17dBm, 500mW 27dBm
- B100mW 20dBm, 50mW 27dBm, 500mW 30dBm
- C100mW 20dBm, 50mW 17dBm, 500mW 27dBm
- D100mW 20dBm, 500mW 17dBm, 500mW 27dBm
76 SNR is the [blank_start]difference in decibels[blank_end] between the [blank_start]received signal[blank_end] and the background [blank_start]noise level[blank_end] (noise floor). The signal strength is not enough to determine quality of signal. Noise Floor is the ambient or background level of radio energy on a specific channel.
- Adifference in decibels
- Breceived signal
- Cnoise level
77 The lower the power level that the receiver can successfully process, the better the receive sensitivity
- ARichtig
- BFalsch
78Link Budget
- AThe amplitude needed to provide stable and useable wireless connectivity
- BThe sum of all gains and losses from the transmitting system through the air (medium) to the intended receiving system
- CIncludes all forms of gain and loss along the path including FSPL and interference
- DLoss between transceiver and antenna, gain at antenna, loss in medium, gain at antenna, loss transceiver.
79Point to point Link, Look at losses and stuff. Ans: Just memorize
- AJust memorize
80Beamwidth
- AMeasurement of how broad or narrow the focus of an antenna is
- BMeasured both horizontally and vertically
- CMeasurement from the strongest point on polar chart to the
half power (-3 dB) point. Imagine cone - DTypes of antennas: omnidirectional, patch/panel, yogi, sector, parabolic dish
81Omni directional antennas
- ADipole antenna is typical, Coverage pattern is bagel shaped, Typically used for point-to-multipoint networks, top view circular, side varies with gain.
- BTriipole antenna is typical, Coverage pattern is diamond shaped, Typically used for point-to-multipoint networks, top view circular, side varies with gain
82Three types of semi directional antennas which direct signal in a specific direction.
- APatch
- BPanel
- CYagi
- DOmnidirectional
83Highly directional antennas:
- AMost focused, narrow beamwidth, Most focused, narrow beamwidth
- BParabolic Dish, grid types
- Cyagi
- DGrid antenna less susceptible to wind load
- EParabolic dish antenna less susceptible to wind load
84 What is false about Static Beamforming ?
- AUses directional antennas to provide a fixed radiation pattern
- BAlso known as sectorized array
- Coverlap improves roaming.
- Dchannels parallel to each other.
- Emultidirectional and changes shape
85Dynamic beam forming is:
- AFocuses the RF energy in a specific direction and particular shape in the direction of an individual client
- BBroadcast frames are sent omnidirectionally
- CPattern can change on a frame-by-frame basis
- Dses an adaptive antenna array
86Transmit beam forming is technically not an antenna technology, but digital signal technology. Multiple phase-shifted signals are transmitted to arrive in-phase at the location of the receiver
- ARichtig
- BFalsch
87Only frequency and distance effect size of Fresnel zone (affected by antenna gain)
- ARichtig
- BFalsch
88Fresnel Zone
- A> 40 percent obstruction will likely make the link unreliable
- BObstruction of first Fresnel zone will negatively influence the integrity of the RF communication
- CImaginary American football-shaped area that surrounds the visual LOS between two point-to-point antennas
89Transmitting and receiving antennas must have the same orientation
- ARichtig
- BFalsch
90MIMO antennas enhance?
- AReliability
- BRange
- CThroughput
- DAmplitude
- EPhase
Informationen
- Beschreibung
- Quiz am Wireless Networking Quiz, erstellt von Upma Sharma am 29/09/2018.
- Autor
- Upma Sharma
- Sprache
- English
- Aufrufe
- 1
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