martes, 20 de enero de 2015

CNA Wireless Chapter 1 and Chapter 2 answers

1.With radio frequencies, the goal is…

to send as much data as possible
as far as possible
as fast as possible
2.The IEEE wireless standard is…
802.11

3.The FCC defines (4 things)
Unlicensed frequencies
Power @ which frequencies can be transmitted at
Transmission technologies which can be used
Locations WLAN dev’s can be deployed
4.The European equivalent of the FCC is called
ETSI: European Telecommunications Standards Institute
5.To achieve bandwidth from RF, an _____________ method is needed, for example ______________
emission method
example: spread spectrum
6.To place data on RF signals, a __________ method is required
modulation method
7.Modulation is…
The addition of data to a carrier signal
8.As data is placed on a signal, more ______________ aka _________________ is used
frequency spectrum or bandwidth
9.In wireless terminology, bandwidth refers to…
The width of the RF channel
10.Hertz can be described as…
Cycles /second
11.Extremely low frequency range = 3-30hz
12.Super low frequency range = 30-300hz
13.Ultra low frequency range = 300hz-3khz
14.Very low frequency range = 3khz-30khz
15.Low frequency range = 30khz-300khz
16.Medium frequency range = 300khz-3mhz
17.High frequency range = 3mhz-30mhz
18.Very high frequency range = 30mhz-300mhz
19.Ultra high frequency range = 300mhz-3ghz
20.Super high frequency range = 3ghz-30ghz
21.Extremely high frequency range = 30ghz-300ghz
22.The 900mhz band’s range is 902mhz-928mhz
23.The 2.4ghz band is used by which 3 wireless standards?
802.11b,g, and n
24.The 2.4ghz band’s range is
2.400ghz – 2.4835ghz
25.The 2.4ghz band has ____ channels
11
26.The 2.4ghz band’s channels are _____ wide
22mhz
27.Which channels in the 2.4ghz range do not overlap?
1, 6 and 11
28.The 2.4ghz band uses _______ modulation
DSSS: direct sequence spread spectrum modulation
29.What standards use the 5ghz band?
802.11a and n
30.The data rate range of 802.11a is
6-54mbps
31.In the 5ghz band, channels are _____ wide
20mhz
32.The 5ghz band has _______ channels
23
33.The 5ghz band uses _________ modulation
OFDM
34.The data rates available inside the 5ghz band are:
6,9,12,18,24,36,48 and 54mbps
35.Define modulation:
Varying in a signal or a tone called a carrier signal
36.Define encoding:
When data is added to that signal
37.A modulated waveform consists of 3 parts
1) amplitude; strength of signal
2) phase; the timing of signal between peaks
3) frequency; how often signal repeats /sec
38.In DSSS, the transmitted signal is spread
across the entire channel
39.Every data bit in DSSS is sent as a
chip stream
40.How many bits need to change in a chip stream before the bit is miscommunicated
5 or more
41.802.11 1 & 2 mbps use which encoding method?
barker code
42.802.11 5.5 and 11mbps use which encoding method?
cck: complimentary code keying
43.How many key words does cck have?
64
44.Each key word in cck communicates how many bits?
up to 6
45.802.11b uses DBPSK and DQPSK modulation, what are these?
These are methods of representing information by changing the phase of the signal
46.What is DBPSK?
Two phases are separated by 180 degrees, DBPSK modulates 1 bit per symbol
47.In DBPSK, a 180 degree phase shift = 1
48.In DBPSK, a zero degree phase shift = 0
49.Is OFDM considered a spread spectrum technology?
no
50.Channels in OFDM are divided into 20mhz, each subcarrier within these channels is 312.5hz wide
51.MIMO is used by
802.11n
52.As distance from AP increases, data rates
decrease
53.What is DRS?
Dynamic rate shifting
The data rate can be dynamically shifted without the connection being dropped
54.CSMA/CD uses a ___________ field to tell other transmitters how long it needs the channel for
duration field
55.The FCC is the federal communications commission
56.Cisco antennae use the __________ connector which stands for
RP-TNC (reverse polarity thread neil concelman connector)
57.What is the measurement for the power emitted by an antenna?
EIRP: effective isotropic radiated power
58.P2MP rules:
36dbm EIRP max
30dbm transmitter power
6db gain of antenna and cable combined
A 1:1 ratio of power to gain

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