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| 1 | |
In a frequency-domain plot, the horizontal axis measures the ________. |
| | A) | signal amplitude |
| | B) | frequency |
| | C) | phase |
| | D) | time |
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| 2 | |
In a time-domain plot, the horizontal axis is a measure of ________. |
| | A) | signal amplitude |
| | B) | frequency |
| | C) | phase |
| | D) | time |
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| 3 | |
_______ data are continuous and take continuous values. |
| | A) | analog |
| | B) | digital |
| | C) | analog or digital |
| | D) | None of the choices are correct. |
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| 4 | |
_______ data have discrete states and take discrete values. |
| | A) | analog |
| | B) | digital |
| | C) | analog or digital |
| | D) | None of the choices are correct. |
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| 5 | |
_____ signals have an infinite number of values in a time interval. |
| | A) | Analog |
| | B) | Digital |
| | C) | Either analog or digital |
| | D) | None of the choices are correct. |
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| 6 | |
_______ signals can have only a limited number of values in a time interval. |
| | A) | Analog |
| | B) | Digital |
| | C) | Either analog or digital |
| | D) | None of the choices are correct. |
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| 7 | |
Frequency and period are ______. |
| | A) | inverse of each other |
| | B) | proportional to each other |
| | C) | the same |
| | D) | are not related |
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| 8 | |
________ is the rate of change with respect to time. |
| | A) | Amplitude |
| | B) | Time |
| | C) | Frequency |
| | D) | Phase |
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| 9 | |
_______ describes the position of the waveform relative to time 0. |
| | A) | Amplitude |
| | B) | Time |
| | C) | Frequency |
| | D) | Phase |
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| 10 | |
A simple sine wave can be represented by one single spike in the _____ domain. |
| | A) | amplitude |
| | B) | time |
| | C) | frequency |
| | D) | phase |
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| 11 | |
As frequency increases, the period ________. |
| | A) | decreases |
| | B) | increases |
| | C) | remains the same |
| | D) | None of the choices are correct. |
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| 12 | |
________ is a type of transmission impairment in which the signal loses strength due to the resistance of the transmission medium. |
| | A) | Attenuation |
| | B) | Distortion |
| | C) | Noise |
| | D) | Decibel |
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| 13 | |
________ 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 |
| | B) | Distortion |
| | C) | Noise |
| | D) | Decibel |
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| 14 | |
________ is a type of transmission impairment in which an outside source such as crosstalk corrupts a signal. |
| | A) | Attenuation |
| | B) | Distortion |
| | C) | Noise |
| | D) | Decibel |
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| 15 | |
When propagation speed is multiplied by propagation time, we get the ________. |
| | A) | throughput |
| | B) | wavelength of the signal |
| | C) | distortion factor |
| | D) | distance a signal or bit has traveled |
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| 16 | |
Baseband transmission of a digital signal is possible only if we have a ____ channel. |
| | A) | low-pass |
| | B) | bandpass |
| | C) | low rate |
| | D) | high rate |
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| 17 | |
If the available channel is a ____ channel, we cannot send a digital signal directly to the channel. |
| | A) | low-pass |
| | B) | bandpass |
| | C) | low rate |
| | D) | high rate |
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| 18 | |
For a ______ channel, the Nyquist bit rate formula defines the theoretical maximum bit rate. |
| | A) | noisy |
| | B) | noiseless |
| | C) | bandpass |
| | D) | low-pass |
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| 19 | |
For a ______ channel, we need to use the Shannon capacity to find the maximum bit rate. |
| | A) | noisy |
| | B) | noiseless |
| | C) | bandpass |
| | D) | low-pass |
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| 20 | |
_________ can impair a signal. |
| | A) | Attenuation |
| | B) | Distortion |
| | C) | Noise |
| | D) | All of the choices are correct. |
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| 21 | |
The _________ product defines the number of bits that can fill the link. |
| | A) | bandwidth-period |
| | B) | frequency-amplitude |
| | C) | bandwidth-delay |
| | D) | delay-amplitude |
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| 22 | |
Polar and bipolar encoding are types of _______ coding. |
| | A) | line |
| | B) | block |
| | C) | scrambling |
| | D) | None of the choices are correct. |
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| 23 | |
___________ conversion involves three techniques: line coding, block coding, and scrambling. |
| | A) | Analog-to-digital |
| | B) | Digital-to-analog |
| | C) | Analog-to-analog |
| | D) | Digital-to-digital |
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| 24 | |
In ______ schemes, the voltage level oscillates between a positive and a negative values although it may remain at zero level between the two values. |
| | A) | polar |
| | B) | bipolar |
| | C) | nonpolar |
| | D) | None of the choices are correct. |
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| 25 | |
In _____, the level of the voltage determines the value of the bit. |
| | A) | NRZ-I |
| | B) | NRZ-L |
| | C) | NRZ-I or NRZ-L |
| | D) | None of the choices are correct. |
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| 26 | |
In ______, the change or lack of change in the level of the voltage determines the value of the bit. |
| | A) | NRZ-I |
| | B) | NRZ-L |
| | C) | NRZ-I or NRZ-L |
| | D) | None of the choices are correct. |
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| 27 | |
The idea of RZ and the idea of NRZ-L are combined into the ________ scheme. |
| | A) | Manchester |
| | B) | differential Manchester |
| | C) | Manchester or differential Manchester |
| | D) | None of the choices are correct. |
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| 28 | |
The idea of RZ and the idea of NRZ-I are combined into the ________ scheme. |
| | A) | Manchester |
| | B) | differential Manchester |
| | C) | Manchester or differential Manchester |
| | D) | None of the choices are correct. |
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| 29 | |
In Manchester and differential Manchester encoding, the transition at the middle of the bit is used for __________. |
| | A) | bit transfer |
| | B) | baud transfer |
| | C) | synchronization |
| | D) | None of the choices are correct. |
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| 30 | |
In _______ encoding, we use three levels: positive, zero, and negative. |
| | A) | polar |
| | B) | bipolar |
| | C) | nonpolar |
| | D) | None of the choices are correct. |
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| 31 | |
The _____ scheme uses data patterns of size 2 and encodes the 2-bit patterns as one signal element belonging to a four-level signal. |
| | A) | 4B5B |
| | B) | 2B1Q |
| | C) | B8ZS |
| | D) | None of the choices are correct. |
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| 32 | |
_______ encoding has a transition at the middle of each bit. |
| | A) | RZ |
| | B) | Manchester |
| | C) | Differential Manchester |
| | D) | All the choices are correct. |
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| 33 | |
_______ encoding has a transition at the beginning of each 0 bit. |
| | A) | RZ |
| | B) | Manchester |
| | C) | Differential Manchester |
| | D) | All the choices are correct. |
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| 34 | |
Which of the following encoding methods does not provide for synchronization? |
| | A) | NRZ-L |
| | B) | RZ |
| | C) | NRZ-I |
| | D) | Manchester |
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| 35 | |
Which encoding method uses alternating positive and negative values for 1s? |
| | A) | NRZ-I |
| | B) | RZ |
| | C) | Manchester |
| | D) | AMI |
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| 36 | |
Block coding can help in _______ and _________ at the receiver. |
| | A) | synchronization and error detection |
| | B) | synchronization and attenuation |
| | C) | error detection and attenuation |
| | D) | error detection and distortion |
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| 37 | |
________ is the process of converting digital data to a digital signal. |
| | A) | Block coding |
| | B) | Line coding |
| | C) | Scrambling |
| | D) | All of the choices are correct. |
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| 38 | |
_______ provides redundancy to ensure synchronization and inherent error detection. |
| | A) | Block coding |
| | B) | Line coding |
| | C) | Line coding or block coding |
| | D) | None of the choices are correct |
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| 39 | |
________ is normally referred to as mB/nB coding; it replaces each m-bit group with an n-bit group. |
| | A) | Block coding |
| | B) | Line coding |
| | C) | Scrambling |
| | D) | None of the choices are correct. |
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| 40 | |
________ provides synchronization without increasing the number of bits. |
| | A) | Scrambling |
| | B) | Line coding |
| | C) | Block coding |
| | D) | None of the choices are correct. |
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| 41 | |
Two common scrambling techniques are ________. |
| | A) | NRZ and RZ |
| | B) | AMI and NRZ |
| | C) | B8ZS and HDB3 |
| | D) | Manchester and differential Manchester |
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| 42 | |
PCM is an example of _______ conversion. |
| | A) | digital-to-digital |
| | B) | digital-to-analog |
| | C) | analog-to-analog |
| | D) | analog-to-digital |
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| 43 | |
The most common technique to change an analog signal to digital data is called __________. |
| | A) | PAL |
| | B) | PCM |
| | C) | sampling |
| | D) | None of the choices are correct. |
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| 44 | |
The first step in PCM is ________. |
| | A) | quantization |
| | B) | modulation |
| | C) | sampling |
| | D) | None of the choices are correct. |
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| 45 | |
______ finds the value of the signal amplitude for each sample; ____ finds the change from the previous sample. |
| | A) | DM; PCM |
| | B) | PCM; DM |
| | C) | DM; CM |
| | D) | None of the choices are correct. |
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| 46 | |
The ________ rate defines the number of data elements sent in one second; the ______ rate is the number of signal elements sent in one second. |
| | A) | data; signal |
| | B) | signal; data |
| | C) | baud; bit |
| | D) | none of the choices are correct |
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| 47 | |
ASK, PSK, FSK, and QAM are examples of ________ conversion. |
| | A) | digital-to-digital |
| | B) | digital-to-analog |
| | C) | analog-to-analog |
| | D) | analog-to-digital |
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| 48 | |
AM, FM, and PM are examples of ________ conversion. |
| | A) | digital-to-digital |
| | B) | digital-to-analog |
| | C) | analog-to-analog |
| | D) | analog-to-digital |
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| 49 | |
In QAM, both ________ of a carrier frequency are varied. |
| | A) | frequency and amplitude |
| | B) | phase and frequency |
| | C) | amplitude and phase |
| | D) | none of the choices are correct |
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| 50 | |
In ________, the amplitude of the carrier signal is varied to create signal elements. Both frequency and phase remain constant. |
| | A) | ASK |
| | B) | PSK |
| | C) | FSK |
| | D) | QAM |
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| 51 | |
In _________, the frequency of the carrier signal is varied to represent data. Both peak amplitude and phase remain constant. |
| | A) | ASK |
| | B) | PSK |
| | C) | FSK |
| | D) | QAM |
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| 52 | |
In ________, the phase of the carrier is varied to represent two or more different signal elements. Both peak amplitude and frequency remain constant. |
| | A) | ASK |
| | B) | PSK |
| | C) | FSK |
| | D) | QAM |
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| 53 | |
Quadrature amplitude modulation (QAM) is a combination of ___________. |
| | A) | ASK and FSK |
| | B) | ASK and PSK |
| | C) | PSK and FSK |
| | D) | None of the choices are correct. |
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| 54 | |
________ uses two carriers, one in-phase and the other quadrature. |
| | A) | ASK |
| | B) | PSK |
| | C) | FSK |
| | D) | QAM |
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| 55 | |
How many carrier frequencies are used in BASK? |
| | A) | 1 |
| | B) | 2 |
| | C) | 3 |
| | D) | None of the choices are correct. |
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| 56 | |
How many carrier frequencies are used in BFSK? |
| | A) | 1 |
| | B) | 2 |
| | C) | 3 |
| | D) | None of the choices are correct. |
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| 57 | |
How many carrier frequencies are used in BPSK? |
| | A) | 1 |
| | B) | 2 |
| | C) | 3 |
| | D) | None of the choices are correct. |
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| 58 | |
Which of the following is not an analog-to-analog conversion? |
| | A) | AM |
| | B) | PM |
| | C) | FM |
| | D) | QAM |
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| 59 | |
In _____ transmission, the carrier signal is modulated so that its amplitude varies with the changing amplitudes of the modulating signal. |
| | A) | AM |
| | B) | PM |
| | C) | FM |
| | D) | None of the choices are correct. |
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| 60 | |
Which multiplexing technique is used for analog signals? |
| | A) | FDM |
| | B) | TDM |
| | C) | WDM |
| | D) | PDM |
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| 61 | |
Which multiplexing technique is used for digital signals? |
| | A) | FDM |
| | B) | TDM |
| | C) | WDM |
| | D) | PDM |
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| 62 | |
Which multiplexing technique shifts each signal to a different carrier frequency? |
| | A) | FDM |
| | B) | TDM |
| | C) | WDM |
| | D) | PDM |
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| 63 | |
Which multiplexing technique involves signals composed of light beams? |
| | A) | FDM |
| | B) | TDM |
| | C) | WDM |
| | D) | PDM |
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| 64 | |
________ is the set of techniques that allows the simultaneous transmission of multiple signals across a single data link. |
| | A) | Demodulating |
| | B) | Multiplexing |
| | C) | Compressing |
| | D) | None of the choices are correct |
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| 65 | |
____ is designed to use the high bandwidth capability of fiber-optic cable. |
| | A) | FDM |
| | B) | TDM |
| | C) | WDM |
| | D) | None of the choices are correct. |
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| 66 | |
______ is an analog multiplexing technique to combine optical signals. |
| | A) | FDM |
| | B) | TDM |
| | C) | WDM |
| | D) | None of the choices are correct. |
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| 67 | |
_____ is a digital process that allows several connections to share the high bandwidth of a link. |
| | A) | FDM |
| | B) | TDM |
| | C) | WDM |
| | D) | None of the choices are correct. |
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| 68 | |
We can divide ____ into two different schemes: synchronous or statistical. |
| | A) | FDM |
| | B) | TDM |
| | C) | WDM |
| | D) | None of the choices are correct. |
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| 69 | |
In ________ TDM, each input connection has an allotment in the output even if it is not sending data. |
| | A) | synchronous |
| | B) | statistical |
| | C) | isochronous |
| | D) | None of the choices are correct. |
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| 70 | |
In ________ TDM, slots are dynamically allocated to improve bandwidth efficiency. |
| | A) | synchronous |
| | B) | statistical |
| | C) | isochronous |
| | D) | None of the choices are correct. |
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| 71 | |
The _______ technique uses M different carrier frequencies that are modulated by the source signal. At one moment, the sign modulates one carrier frequency; at the next moment, the signal modulates another carrier frequency. |
| | A) | FDM |
| | B) | DSSS |
| | C) | FHSS |
| | D) | TDM |
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| 72 | |
The ______ technique expands the bandwidth of a signal by replacing each data bit with n bits using a spreading code. |
| | A) | FDM |
| | B) | DSSS |
| | C) | FHSS |
| | D) | TDM |
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| 73 | |
Transmission media are usually categorized as _______. |
| | A) | fixed or unfixed |
| | B) | guided or unguided |
| | C) | determinate or indeterminate |
| | D) | metallic or nonmetallic |
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| 74 | |
Transmission media lie below the _______ layer. |
| | A) | physical |
| | B) | network |
| | C) | transport |
| | D) | application |
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| 75 | |
_______ cable consists of an inner copper core and a second conducting outer sheath. |
| | A) | Twisted-pair |
| | B) | Coaxial |
| | C) | Fiber-optic |
| | D) | Shielded twisted-pair |
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| 76 | |
In fiber optics, the signal is _______ waves. |
| | A) | light |
| | B) | radio |
| | C) | infrared |
| | D) | very low-frequency |
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| 77 | |
Which of the following is not a guided medium? |
| | A) | twisted-pair cable |
| | B) | coaxial cable |
| | C) | fiber-optic cable |
| | D) | atmosphere |
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