Deck 2: Fundamentals of Data and Signals

Question 1

The big disadvantage of the Manchester schemes is that roughly half the time there will be two transitions during each bit.

Answer 1

True

Question 2

A sine wave is common example used to demonstrate an analog signal.

Answer 2

True

Question 3

The telephone system transmits signals in the range of 150 Hz to 1500 Hz.

Answer 3

False

Question 4

Frequency shift keying is susceptible to sudden noise spikes that can cause loss of data.

Question 5

The ability to separate noise from a digital waveform is one of the great strengths of digital systems.

Question 6

The period of a signal can be calculated by taking the reciprocal of the frequency (1/frequency).

Question 7

Under some circumstances,the baud rate may equal the bps,such as in the Manchester encoding schemes.

Question 8

Attenuation in a medium such as copper wire is a logarithmic loss and is a function of distance and the resistance within the wire.

Question 9

With NRZI,the receiver has to check the voltage level for each bit to determine whether the bit is a 0 or a 1.

Question 10

Telephones,AM radio,FM radio,broadcast television,and cable television are the most common examples of analog data-to-digital signal conversion.

Question 11

With NRZ-L,the receiver has to check whether there is a change at the beginning of the bit to determine if it is a 0 or a 1.

Question 12

Like signals,data can be analog or digital.

Question 13

The NRZ-L encoding scheme is simple to generate and inexpensive to implement in hardware.

Question 14

The terms "data" and "signal" mean the same thing.

Question 15

Phase changes are not affected by amplitude changes,nor are they affected by intermodulation distortions.

Question 16

Amplitude shift keying is restricted to only two possible amplitude levels: low and high.

Question 17

By convention,the minimum and maximum values of analog data and signals are presented as voltages.

Question 18

Amplitude shift keying is susceptible to sudden noise impulses such as the static charges created by a lightning storm.

Question 19

An inherent problem with the NRZ-L and NRZI digital encoding schemes is that long sequences of 0s in the data produce a signal that never changes.

Question 20

One of the primary shortcomings of analog data and analog signals is how difficult it is to separate noise from the original waveform.

Question 21

Cycles per second,or frequency,is represented by ____.

A) bytes
B) hertz
C) bits
D) watts

Question 22

The amplitude of a signal can be expressed as volts,____,or watts.

A) hertz
B) amps
C) bits
D) bytes

Question 23

The ____ of a signal is the number of times a signal makes a complete cycle within a given time frame.

A) phase
B) amplitude
C) period
D) frequency

Question 24

One of the most common forms of data transmitted between a transmitter and a receiver is textual data.

Question 25

A byte consists of 8 bits.

Question 26

The most common example of ____ data is the human voice.

A) sampling
B) baud
C) digital
D) analog

Question 27

____ are entities that convey meaning within a computer or computer system.

A) Signals
B) Data
C) Impulse
D) EMI

Question 28

Certain control characters provide data transfer control between a computer source and computer destination.

Question 29

ASCII is a data code rarely used in the world.

Question 30

The bps of the data transmitted using quadrature amplitude modulation is four times the baud rate.

Question 31

The three basic components of analog and digital signals are: amplitude,frequency,and ____.

A) cycles
B) baud
C) hertz
D) phase

Question 32

Unfortunately,noise itself occurs as a(n)____ waveform,and this makes it challenging,if not extremely difficult,to separate noise from an analog waveform that represents data.

A) analog
B) digital
C) hertz
D) byte

Question 33

____ are represented as continuous waveforms that can be at an infinite number of points between some given minimum and maximum.

A) Analog signals
B) Digital signals
C) Digital data
D) Digital pulses

Question 34

____ are discrete waveforms,rather than continuous waveforms.

A) Analog signals
B) Analog bauds
C) Digital signals
D) Analog data

Question 35

ASCII is one of the supported code charts in Unicode.

Question 36

If you want to transfer data from one point to another,either via a physical wire or through radio waves,the data has to be converted into a(n)____.

A) hertz
B) Unicode
C) signal
D) byte

Question 37

In Unicode,the letter "r" is represented by the binary value of 0000 0000 0101 0100 0010.

Question 38

One of the major problems with Unicode is that it cannot represent symbols other than those found in the English language.

Question 39

According to a famous communications theorem created by Nyquist,the sampling rate using pulse code modulation must be at least three times the highest frequency of the original analog waveform.

Question 40

IBM mainframe computers are major users of the EBCDIC character set.

Question 41

The Manchester encoding schemes are called ____,because the occurrence of a regular transition is similar to seconds ticking on a clock.

A) continuous-clocking
B) analog-clocking
C) discrete-clocking
D) self-clocking

Question 42

The number of times a signal changes value per second is called the ____ rate.

A) hertz
B) baud
C) watts
D) volts

Question 43

The data rate is measured in ____.

A) bits per second (bps)
B) bytes per second (Bps)
C) bauds per second (bps)
D) hertz per second (hps)

Question 44

The ____ encoding scheme has a voltage change at the beginning of a 1 and no voltage change at the beginning of a 0.

A) nonreturn to zero inverted (NRZI)
B) nonreturn to zero-level (NRZ-L)
C) Manchester
D) Differential Manchester

Question 45

The frequency range of the average human voice usually goes no lower than 300 Hz and no higher than approximately ____ Hz.

A) 2200
B) 2400
C) 3400
D) 5300

Question 46

Three currently popular modulation techniques for encoding digital data and transmitting it over analog signals are amplitude shift keying,frequency shift keying,and ____ shift keying.

A) noise
B) baud
C) strength
D) phase

Question 47

The ____ digital encoding scheme is similar to the Manchester scheme in that there is always a transition in the middle of the interval.

A) NRZ-L
B) Bipolar-AMI
C) differential Manchester
D) NRZI

Question 48

The Manchester encoding schemes solve the synchronization problem but are relatively inefficient because they have a baud rate that is ____ the bps.

A) equal to
B) twice
C) three times
D) four times

Question 49

The primary advantage of a bipolar scheme is that when all the voltages are added together after a long transmission,there should be a total voltage of ____.

A) -2
B) -1
C) 0
D) 1

Question 50

When traveling through any type of medium,a signal always experiences some loss of its power due to friction.This loss of power,or loss of signal strength,is called ____.

A) amplification
B) friction
C) decibel
D) attenuation

Question 51

Frequency shift keying is subject to ____.

A) baud noise
B) bps distortion
C) intermodulation distortion
D) noise spikes

Question 52

____ is the process of sending data over a signal by varying either its amplitude,frequency,or phase.

A) Amplification
B) Modulation
C) Attenuation
D) Digital encoding

Question 53

The simplest modulation technique is ____ shift keying.

A) amplitude
B) phase
C) frequency
D) noise

Question 54

____ shift keying represents 0s and 1s by different changes in the phase of a waveform.

A) Amplitude
B) Phase
C) Frequency
D) Noise

Question 55

The lowest note possible on the piano is ____ Hz,and the highest note possible is 4200 Hz.

A) 30
B) 80
C) 300
D) 450

Question 56

When a signal is amplified by an amplifier,the signal gains in ____.

A) decibels
B) hertz
C) bytes
D) watts

Question 57

____ shift keying incorporates four different phase angles,each of which represents 2 bits.

A) Quadrature amplitude
B) Quadrature frequency
C) Quadrature noise
D) Quadrature phase

Question 58

The bandwidth of a telephone system that transmits a single voice in the range of 300 Hz to 3400 Hz is ____ Hz.

A) 10
B) 100
C) 3100
D) 3700

Question 59

Using ____,when a device transmits a binary 0,a zero voltage is transmitted.When the device transmits a binary 1,either a positive voltage or a negative voltage is transmitted.

A) Manchester
B) bipolar-AMI
C) differential Manchester
D) NRZ-L

Question 60

A device that modulates digital data onto an analog signal and then demodulates the analog signal back to digital data is a ____.

A) repeater
B) switch
C) hub
D) modem

Question 61

____________________ are the electric or electromagnetic impulses used to encode and transmit data.

Question 62

With ____,a codec tracks the incoming analog data by assessing up or down "steps."

A) differential Manchester
B) Bipolar-AMI
C) NRZI
D) delta modulation

Question 63

____________________ is unwanted electrical or electromagnetic energy that degrades the quality of signals and data.

Question 64

The ____________________ of a signal is the height of the wave above (or below)a given reference point.

Question 65

____ is an 8-bit code allowing 256 possible combinations of textual symbols.

A) EBCDIC
B) Unicode
C) NRZI
D) UTF-9

Question 66

Tracking an analog waveform and converting it to pulses that represent the wave's height above (or below)a threshold is termed ____.

A) pulse amplitude modulation (PAM)
B) codec
C) quantization
D) quantization levels

Question 67

The ____________________ of a signal is the position of the waveform relative to a given moment of time,or relative to time zero.

Question 68

The range of frequencies that a signal spans from minimum to maximum is called the ____________________.

Question 69

The ____________________ of a signal is the absolute value of the difference between the lowest and highest frequencies.

Question 70

The ____________________,or time interval,of one cycle is called its period.

Question 71

Because extraneous noise degrades original signals,an electronic device usually has a(n)____________________ that is less than its bandwidth.

Question 72

Three important data codes are EBCDIC,____,and Unicode.

A) NRZ-L
B) 4B/5B
C) ASCII
D) NRZI

Question 73

The ____ is a government standard in the United States.

A) UTF-8
B) EBCDIC
C) American Standard Code for Information Interchange (ASCII)
D) Unicode

Question 74

____________________ is a relative measure of signal loss or gain and is used to measure the logarithmic loss or gain of a signal.

Question 75

Converting analog data to digital signals is generally called ____________________.

Question 76

The ASCII character set exists in a few different forms,including a ____ version that allows for 128 possible combinations of textual symbols.

A) 3-bit
B) 5-bit
C) 6-bit
D) 7-bit

Question 77

The Unicode character set uses ______ bit characters.

A) 4
B) 8
C) 16
D) 32

Question 78

One encoding technique that converts analog data to a digital signal is ____.

A) NRZ-L
B) Manchester
C) pulse code modulation (PCM)
D) NRZ-I

Question 79

____ modulation,which is commonly employed in contemporary modems,uses each signal change to represent 4 bits.

A) Quadrature amplitude
B) Quadrature frequency
C) Quadrature noise
D) Quadrature phase

Question 80

When converting analog data to digital signals,the frequency at which the snapshots are taken is called the ____ rate.

A) baud
B) sampling
C) bps
D) byte