Forouzan Data Comm Chapter 3 Multiple Choice 3,4,5th Edition
_______ data have discrete states and take discrete values. A) Analog B) Digital C) (a) or (b) D) None of the above
Digital
_______ signals can have only a limited number of values. A) Digital B) Analog C) (a) or (b) D) None of the above
Digital
________ is a type of transmission impairment in which the signal loses strength due to the different propagation speeds of each frequency that makes up the signal. A) Noise B) Distortion C) Attenuation D) Decibel
Distortion
________________ is a type of transmission impairment in which the signal loses strength due to the different propagation speeds of each frequency that makes up the signal. a. Attenuation c. Noise b. Distortion d. Decibel
Distortion
Bit rate and bit interval are used to describe analog signals. True or False
False
Continuous range of values is a signal that represents a digital signal. True or False
False
The Nyquist rate is a formula used to determine the theoretical maximum data rate for a noisy channel. True or False
False
The Shannon capacity is a formula used to determine the theoretical data rate for a noiseless channel. True or False
False
________is the rate of change with respect to time. A) Time B) Frequency C) Amplitude D) Voltage
Frequency
________ is a type of transmission impairment in which an outside source such as crosstalk corrupts a signal. A) Noise B) Distortion C) Attenuation D) Decibel
Noise
____________________ is a type of transmission impairment in which an outside source such as crosstalk corrupts a signal. a. Attenuation c. Noise b. Distortion d. Decibel
Noise
Data can be ________. A) digital B) analog C) (a) or (b) D) none of the above
(a) or (b)
If the maximum amplitude of a sine wave is 2 V, the minimum amplitude is ________ V. A) 2 B) 1 C) -2 D) between -2 and 2
-2
A periodic signal completes one cycle in 0.001 s. What is the frequency? A) 1 Hz B) 100 Hz C) 1 KHz D) 1 MHz
1 KHz
What is the bandwidth of a signal that ranges from 1 MHz to 4 MHz? A) 1 KHz B) 3 MHz C) 4 MHz D) none of the above
3 MHz
What is the bandwidth of a signal that ranges from 40 kHz to 4 MHz? a. 36 MHz c. 3.96 MHz b. 360 kHz d. 396 kHz
360 kHz
If the bandwidth of a signal is 5 KHz and the lowest frequency is 52 KHz, what is the highest frequency? A) 5 KHz B) 47 KHz C) 57 KHz D) 10 KHz
57 KHz
If the bandwidth of a signal is 5 kHz and the lowest frequency is 52 kHz, what is the highest frequency of the bandwidth while the signal is in transit along the media? a. 5 kHz c. 47 kHz b. 37 kHz d. 57 kHz
57 kHz
Frequency is the rate of change with respect to time. This means that: a. change in a short span of time means high frequency c. Period is the inverse of frequency b. change in a long span of time means low frequency d. All of the above
All of the above
These can impair a signal on a network: a. attenuation c. noise b. distortion d. All of the above.
All of the above
_________ can impair a signal. A) Noise B) Attenuation C) Distortion D) All of the above
All of the above
A fundamental difference between analog and digital signals are: a. analog bandwidth is measured in kHz and digital bandwidth is measured in bits per second. b. analog signals are continuous ranges of values and digital signals are discrete, aperiodic signals. c. analog signals are periodic signals that pass a range of frequencies and digital signals are aperiodic signals. d. All of the above.
All of the above.
_____ signals can have an infinite number of values in a range. A) Analog B) Digital C) (a) or (b) D) None of the above
Analog
________ is a type of transmission impairment in which the signal loses strength due to the resistance of the transmission medium. A) Distortion B) Attenuation C) Noise D) Decibel
Attenuation
A signal is measured at two different points. The power is P1 at the first point and P2 at the second point. The dB is 0. This means ________. A) P2 equals P1 B) P2 is zero C) P2 is much larger than P1 D) P2 is much smaller than P1
P2 equals P1
_______ describes the position of the waveform relative to time 0. A) Amplitude B) Phase C) Frequency D) Voltage
Phase
Describe the three characteristics of a sine wave.
Representative of an analog (periodic) signal, the three characteristics of a sine wave are: amplitude, frequency and phase.
A signal is periodic if it consists of a continuously repeating pattern. One example would be an analog signal in the form of a sine wave. True or False
True
A time-domain graph plots each sine wave's peak amplitude against its frequency. True or False
True
Attenuation is the loss of a signal's strength due to the resistance of the medium. Extending a signal past a recommended maximum cable segment length can cause attenuation. True or False
True
Data must be transformed into electromagnetic signals prior to transmission across a network. True or False
True
Data transmission can be encoded as either analog or digital signals, depending on the respective network media's available bandwidth. True or False
True
Each sine wave can be characterized by its amplitude, frequency and phase. True or False
True
Electromagnetic Interference (EMI) on a network can be caused by: a. a large electrical source such as an electrical generator operating near an unshielded cable medium. b. electrical storms caused by lightening. c. broadcast storms of a malfunctioning Network Interface Card (NIC). d. All of the above.
a large electrical source such as an electrical generator operating near an unshielded cable medium.
_______ data are continuous and take continuous values. A) digital B) analog C) (a) or (b) D) none of the above
analog
If the available channel is a ____ channel, we cannot send a digital signal directly to the channel. A) low-pass B) low rate C) bandpass D) high rate
bandpass
The _____ of a composite signal is the difference between the highest and the lowest frequencies contained in that signal. A) period B) bandwidth C) frequency D) amplitude
bandwidth
The _________ product defines the number of bits that can fill the link. A) delay-amplitude B) frequency-amplitude C) bandwidth-period D) bandwidth-delay
bandwidth-delay
Instead of referring to digital signals as having a period and frequency when measuring a signal's bandwidth, one should refer to: a. byte rate and byte interval c. range and force b. bit rate and bit interval d. All of the above
bit rate and bit interval
A signal has been received that only has values in measures of -1, 0 and 1. This is an example of a/an: a. discrete signal c. both A and B. b. digital signal d. None of the above.
both A and B
In essence, a digital signal: a. is a composite signal. c. both A and B b. has an infinite bandwidth d. None of the above
both A and B
As frequency increases, the period ________________. a. decreases b. increases c. maintains at the same rate as at the prior d. doubles
decreases
A(n)_________ signal is a composite analog signal with an infinite bandwidth. A) digital B) analog C) either (a) or (b) D) neither (a) nor (b)
digital
When propagation speed is multiplied by propagation time, we get the ________. A) wavelength of the signal B) throughput C) distance a signal or bit has traveled D) distortion factor
distance a signal or bit has traveled
Before data can be transmitted, they must be transformed to ________. A) periodic signals B) electromagnetic signals C) aperiodic signals D) low-frequency sine waves
electromagnetic signals
Before data can be transmitted, they must be transformed to _______________. a. periodic signals c. aperiodic signals b. electromagnetic signals d. low-frequency sine waves
electromagnetic signals
In a frequency-domain plot, the horizontal axis measures the ________. A) phase B) frequency C) slope D) peak amplitude
frequency
Frequency and period are ______. A) proportional to each other B) inverse of each other C) the same D) none of the above
inverse of each other
Baseband transmission of a digital signal is possible only if we have a ____ channel. high rate low-pass low rate bandpass
low-pass
Baseband transmission of a digital signal is possible only if we have a ____ channel. A) bandpass B) low-pass C) high rate D) low rate
low-pass
For a ______ channel, the Nyquist bit rate formula defines the theoretical maximum bit rate. A) low-pass B) bandpass C) noisy D) noiseless
noiseless
For a ______ channel, we need to use the Shannon capacity to find the maximum bit rate. A) noiseless B) noisy C) low-pass D) bandpass
noisy
A sine wave is ________. A) periodic and discrete B) aperiodic and discrete C) periodic and continuous D) aperiodic and continuous
periodic and continuous
A _________ sine wave is not useful in data communications; we need to send a _______ signal. A) single-frequency; composite B) composite; single-frequency This is the correct answer. C) single-frequency; double-frequency D) none of the above
single-frequency; composite
The performance of transmission media can be measured by ___________________. a. throughput c. propagation time b. propagation speed d. either B or C
throughput
In a time-domain plot, the horizontal axis is a measure of ________. A) phase B) signal amplitude C) frequency D) time
time
A sine wave in the ______ domain can be represented by one single spike in the _____ domain. A) time; phase B) frequency; time C) time; frequency D) phase; time
time; frequency
Given two sine waves A and B, if the frequency of A is twice that of B, then the period of B is ________ that of A. A) one-half B) twice C) the same as D) indeterminate from
twice