Deck 4: Manipulating Information for Transmission

Question 1

In communications, the term ________ refers to information being transmitted using a one state or a zero state.

Answer 1

digital

Question 2

________ signals are difficult to synchronize and hard to monitor with error-checking schemes because there are no opposite polarity pulses to count.

Answer 2

Unipolar

Question 3

The three common digital patterns are ________, bipolar nonreturn to zero (BPNRZ), and bipolar return to zero (BPRZ).

Answer 3

unipolar

Question 4

The most commonly used digital bit pattern and the one most commonly used in the communications network is the:

A) BPNRZ waveform
B) unipolar waveform
C) BPRZ wavef
D) all are used equally

Question 5

Bipolar non-return to zero provides the best method for transmitting digital signals longer distances.

Question 6

The pulse ________ is the shape the pulse should fall within in order to be considered a pulse.

Question 7

A two-way radio is a good example of a:

A) simplex transmission mode
B) half-duplex circuit
C) full-duplex circuit
D) answers a and b above

Question 8

One problem with analog signals is that they have:

A) multiple frequencies to deal with
B) increased noise on the line
C) greater signal degradation
D) complex waveforms
E) all of the above

Question 9

The only analog portion of the network left today is that found between the serving central office and the subscriber's residence.

Question 10

Which of the following is not one of the stages occurring in the process of analog-to-digital conversion?

A) multiplexing
B) sampling
C) quantizing
D) encoding

Question 11

The step that converts a voltage value of the analog waveform to a digital word in analog-to-digital conversion is called ________.

Question 12

________ is the final step in the analog-to-digital conversion process.

Question 13

Each ________ word refers to one sample of an analog waveform.

Question 14

Early scientists determined that ________ eight-bit words sufficiently represent all of the levels of human speech.

Question 15

Sampling is the process that formats the PCM words and ships them out onto the physical transmission medium, whether it is a copper wire or a fiber-optic strand.

Question 16

The Nyquist Theorem states that a waveform should be sampled at eight times its highest frequency in order to obtain a toll quality signal.

Question 17

The term toll ________ refers to a voice signal that meets the toll voice specifications provided by standards organizations.

Question 18

Techniques such as ADPCM and LD-CELP have been created to compress the voice signal and reduce the number of ones and zeros needed for each PCM word.

Question 19

When a digital line interfaces with a PC, the signal has to go through analog-to-digital conversion.

Question 20

The individual signal riding within the multiplexed signal is called a(n) ________.

Question 21

In a digital-to-digital conversion, the interface equipment formats the digital signal into a(n) ________ signal before transmitting it out onto the network.

Question 22

A(n) ________ combines numerous information signals onto one transmission pipe, combining as few as 24 channels onto one T1 transmission link or as many as 129,024 channels onto one fiber-optic strand.

Question 23

________ is the acronym for the multiplexing method that works by dividing the frequency spectrum into subchannels, or frequency chunks, and transporting individual voice signals across each channel.

Question 24

Which of the following is a major problem associated with the use of FDM?

A) power required to energize the circuits
B) the increased noise in the line
C) the task of tuning the circuits
D) all of the above

Question 25

FDM is the most commonly used method of multiplexing today because it represents huge savings in costs.

Question 26

The method that multiplexes digital words into time slots together in one signal is:

A) TDM
B) DWDM
C)ATM
D) PGM

Question 27

FDM is a viable multiplexing method for certain applications such as DSL, which is used for short distances between central offices and subscribers' locations.

Question 28

Which statement about TDM is true?

A) TDM rides on all types of media, copper, radio frequencies, and fiber.
B) TDM is the most widely used transport protocol in the world-wide communications network.
C) TDM uses time slots to carry signals instead of frequencies and multiplexes digital signals into the time slots, not analog signals, as with FDM.
D) There are two distinct steps in the TDM process, conversion and multiplexing.
E) All of the above.

Question 29

The optical standard that defines specific bit-per-second rates is the ________ standard.

Question 30

Which statement concerning fast-packet multiplexing is not true?

A) it is a method used to transmit information
B) it is much more efficient than TDM or FDM
C) it operates on the premise that circuits may be oversubscribed in the same way that stadium seats are oversold, with the understanding that not every subscriber user will be on line at the same time
D) none of the above (all are true)

Question 31

ATM stands for ________ transfer mode, a fast packet transmission protocol that statistically multiplexes fixed-length cells.

Question 32

The newest multiplexing technology in the communications network is:

A) FDM
B) TDM
C) fast-packet
D) DWDM

Question 33

The rapid development of DWDM systems has helped to increase the amount of bandwidth available throughout the world.

Question 34

Fast-packet multiplexing is quickly becoming the multiplexing method of choice.

Question 35

The acronym for systems with very wide spacing fields between each wavelength that limit the number of channels per system is ________.

Question 36

The process of incorporating an information signal onto a carrier wave is called ________.

Question 37

Explain the analog-to-digital conversion process, describing the three steps involved.

Question 38

The most popular encoding scheme for personal computing devices is ________.

Question 39

The acronym for the eight-bit code that IBM developed specifically for their machines, which is seldom deployed today is ________.

Question 40

When information is shipped out onto the medium one bit at a time, it is said to be traveling across the network via parallel transmission.

Question 41

The problem associated with using start and stop bits is the amount of ________ used every time a character is sent.

Question 42

In ________ transmission, the use of one clock to reference the start and stop of the bit stream allows the equipment to send characters without individual stop and start bits.

Question 43

The simplest technique for converting the digital signal to an analog signal is:

A) AM
B) PM
C) FM
D) all are about the same in terms of complexity

Question 44

In analog data transmission, frequencies of 0 to 300 Hz and 3300 to 4000 Hz are reserved as ________, used to ensure that the data transmission will not interfere with other signals.

Question 45

In analog data transmission, frequencies of 0 to 300 Hz and 3300 to 4000 Hz are reserved as ________, used to ensure that the data transmission will not interfere with other signals.

Question 46

How many signaling changes/changes in the waveform occur per second in a 2400 baud per second circuit?

A) 600
B) 1200
C) 1800
D) 2400

Question 47

The amount of data the analog data circuit is able to carry depends on the:

A) type of modem on each end
B) length of the circuit from the subscriber to the central office
C) cable gauge
D) total impedance of the line
E) all of the above

Question 48

________ combines PM and AM to produce a four-bit per baud signal