Deck 8: Multiplexing

Question 1

At a higher level of utilization a larger buffer is needed to hold the backlog.

Answer 1

True

Question 2

The ________ accepts the multiplexed data stream,separates the data according to channel,and delivers data to the appropriate output lines.

A)high capacity fiber
B)coaxial link
C)multiplexer
D)demultiplexer

Answer 2

D

Question 3

Synchronous time division multiplexing can be used with ________ signals.

A)analog
B)digital signals or analog signals carrying digital data
C)digital
D)digital signals carrying digital data

Answer 3

B

Question 4

Large numbers of voice and data transmissions can be carried simultaneously using multiplexing.

Question 5

With time division multiplexing,modulation equipment is needed to move each signal to the required frequency band and multiplexing equipment is needed to combine the modulated signals.

Question 6

Synchronous time division multiplexing is possible when the achievable data rate of the medium exceeds the data rate of digital signals to be transmitted.

Question 7

________ multiplexing is commonly used for multiplexing digitized voice streams and data streams.

A)Time division
B)Frequency division
C)Statistical time division
D)Synchronous time division

Question 8

FDMA is a technique used to share the spectrum among multiple stations.

Question 9

Flow control and error control can be provided on a per-channel basis by using a data link control protocol such as HDLC.

Question 10

The true potential of optical fiber is fully exploited when multiple beams of light at different frequencies are transmitted on the same fiber.

Question 11

The long distance carrier system provided in the US and throughout the world was designed to transmit voice signals over high capacity transmission links such as optical fiber,coaxial cable,and microwave.

Question 12

The multiplexer combines data from the input lines and transmits over a lower capacity data link.

Question 13

Typically two communicating stations will not utilize the full capacity of a data link.

Question 14

Frequency division multiplexing can be used with ________ signals.

A)digital signals carrying digital data
B)analog signals carrying digital data
C)analog
D)digital

Question 15

Multiplexing allows several transmission sources to share a larger transmission capacity.

Question 16

In TDD,data are transmitted in both directions at the same time.

Question 17

The higher the data rate,the least cost-effective the transmission facility.

Question 18

An individual cable modem subscriber may experience access speeds from 500 kbps to 1.5 Mbps or more,depending on the network architecture and traffic load.

Question 19

The ________ multiplexing is the most heavily used.A familiar example is broadcast and cable television.

A)statistical time division
B)time division
C)frequency division
D)synchronous time division

Question 20

Synchronous TDM is called synchronous because synchronous transmission is used.

Question 21

The digital subscriber line combines FDM and ________ technologies.

Question 22

A generic term for sharing the capacity of a data link is ________.

Question 23

In FDM,because multiple carriers are to be used,each is referred to as a ________.

A)subcarrier
B)channel
C)WDM
D)subscriber

Question 24

The schemes for providing high speed digital transmission of the subscriber line are collectively referred to as ________.

A)DMT/QAM
B)SDSL
C)VDSL
D)xDSL

Question 25

________ was developed in the late 1980s by BellCore to provide a more cost effective means of delivering a T1 data rate.

A)xDSL
B)HDSL
C)QAM
D)DMT

Question 26

A __________ is a device that allows a user to access the Internet and other online services through a cable TV network.

Question 27

With ________,the outgoing data rate of the multiplexer,excluding framing bits,is higher than the sum of the minimum instantaneous incoming rates.The extra capacity is used by stuffing extra dummy bits into each incoming signal until its rate is raised to that of a locally generated clock signal.

Question 28

From customer to carrier is ________.

A)symmetric
B)upstream
C)downstream
D)asymmetric

Question 29

With ________ multiplexing a number of signals are carried simultaneously on the same medium by allocating to each signal a different frequency band.

Question 30

________ was developed to provide the same type of service as HDSL but over a single twisted pair line.

A)SDSL
B)QAM
C)VDSL
D)AMI

Question 31

From the carrier's central office to the customer's site is ________.

A)asymmetric
B)upstream
C)headend
D)downstream

Question 32

Two problems that an FDM system must cope with are crosstalk and ________ noise.

A)blanketed
B)amplified
C)intermodulation
D)channeled

Question 33

The two most common forms of multiplexing are frequency division multiplexing and ________.

Question 34

A form of frequency division multiplexing where the light streaming through the fiber consists of many colors,or wavelengths,each carrying a separate channel of data is ________ multiplexing.

Question 35

To support data transfer to and from a cable modem,a cable TV provider dedicates ________ channels.

A)one
B)two
C)four
D)three

Question 36

Each modulated signal requires a certain bandwidth centered on its carrier frequency and referred to as a ________.

Question 37

ADSL uses ________ multiplexing to exploit the capacity of twisted pair.

A)synchronous time division
B)statistical time division
C)time division
D)frequency division

Question 38

The transmitted data in synchronous TDM are organized into ________.

A)blocks
B)frames
C)channels
D)frequencies

Question 39

With ________ multiplexing data from various sources are carried in repetitive frames.

Question 40

When the useful bandwidth of the transmission medium exceeds the required bandwidth of signals to be transmitted,________ multiplexing is possible.

Question 41

________ is a modern technology designed to provide high speed digital data transmission over ordinary telephone wire.

Question 42

________ uses multiple carrier signals at different frequencies,sending some of the bits on each channel.The modem sends out test signals on each subchannel to determine the signal-to-noise ratio.The modem then assigns more bits to channels with better signal transmission and less bits to channels with poorer signal transmission.

Question 43

In ________ modulation,each signal occupies a distinct frequency band so these signals can be combined by simple addition to produce the composite signal for transmission.

Question 44

An optical transmission interface originally proposed by BellCore and standardized by ANSI is ________.It is intended to provide a specification for taking advantage of the high speed digital transmission capacity of optical fiber.

Question 45

The disadvantage of using echo cancellation is the need for ________ logic on both ends of the line.