A sine wave is ________.
1.periodic and continuous
2.aperiodic and continuous
3.periodic and discrete
4.aperiodic and discrete
A _________ sine wave is not useful in data communications; we need to send a _______ signal
1.composite; single-frequency
2.single-frequency; composite
3.single-frequency; double-frequency
4.none of the above
For a ______ channel, the Nyquist bit rate formula defines the theoretical maximum bit rate.
1.noisy
2.noiseless
3.bandpass
4.low-pass
For a ______ channel, we need to use the Shannon capacity to find the maximum bit rate.
1.noisy
2.noiseless
3.bandpass
4.low-pass
If the bandwidth of a signal is 5 KHz and the lowest frequency is 52 KHz, what is the highest frequency?
1. 5 KHz
2.10 KHz
3.47 KHz
4. 57 KHz
If the bandwidth of a signal is 5 KHz and the lowest frequency is 52 KHz, what is the highest frequency?
1. 5 KHz
2.10 KHz
3.47 KHz
4. 57 KHz
The physical layer is concerned with the movement of _______ over the physical medium.
1.programs
2.dialogs
3.protocols
4.bits
The term ......... describes the position of the waveform relative to time 0.
1.Frequency
2.Phase
3.Phase Shift
4.Time period
The _____ of a composite signal is the difference between the highest and the lowest frequencies contained in that signal.
1.frequency
2.period
3.bandwidth
4.amplitude
The _________ product defines the number of bits that can fill the link.
1.bandwidth-period
2. frequency-amplitude
3.bandwidth-delay
4.delay-amplitude
Unipolar, bipolar, and polar encoding are types of _______ encoding. a. line b. block c. NRZ d. Unipolar, bipolar, and polar encoding are types of _______ encoding.
1.line
2.block
3.NRZ
4. Manchester
_____ signals can have an infinite number of values in a range.
1.Analog
2.Digital
3.(a) or (b)
4.None of the above
A periodic signal completes one cycle in 0.001 s. What is the frequency?
1.1 Hz
2.100 Hz
3.1 KHz
4.1 MHz
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 ________.
1.P2 is zero
2.P2 equals P1
3.P2 is much larger than P1
4.P2 is much smaller than P1
A sine wave in the ______ domain can be represented by one single spike in the _____ domain.
1.time; frequency
2.frequency; time
3.time; phase
4. phase; time
A(n)_________ signal is a composite analog signal with an infinite bandwidth.
1.digital
2.analog
3.either (a) or (b)
4.neither (a) nor (b)
As frequency increases, the period ________.
1.decreases
2.increases
3.remains the same
4.doubles
Baseband transmission of a digital signal is possible only if we have a ____ channel.
1.low-pass
2.bandpass
3.low rate
4.high rate
Baud means?
1.The number of bits transmitted per unit time
2.The number of byted transmitted per unit time
3.The rate at which the signal changes
4.None of the above
Before data can be transmitted, they must be transformed to ________.
1.periodic signals
2.electromagnetic signals
3.aperiodic signals
4.low-frequency sine waves
Data can be ________. d. none of the above
1.analog
2.digital
3.(a) or (b)
4.None of the above
Frequency and period are ______.
1.inverse of each other
2.proportional to each other
3.the same
4.None of the above
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.
1.one-half
2.twice
3.the same as
4. indeterminate from
If the available channel is a ____ channel, we cannot send a digital signal directly to the channel.
1. low-pass
2.bandpass
3. low rate
4.high rate
If the maximum amplitude of a sine wave is 2 V, the minimum amplitude is ________ V.
1.2
2.1
3.-2
4.between -2 and 2
In a frequency-domain plot, the horizontal axis measures the ________.
1.peak amplitude
2.frequency
3.phase
4.slope
In a time-domain plot, the horizontal axis is a measure of ________.
1.signal amplitude
2.frequency
3.phase
4.time
In asynchronous serial communication the physical layer provides
1.start and stop signalling
2.flow control
3.both (a) and (b)
4.None of the mentioned
physical layer provides
1.mechanical specifications of electrical connectors and cables
2.electrical specification of transmission line signal level
3.specification for IR over optical fiber
4.all of the mentioned
Signals can be ________.
1.analog
2.digital
3.either (a) or (b)
4.neither (a) nor (b)
The physical layer concerns with
1.bit-by-bit delivery
2.process to process delivery
3.application to application delivery
4.None of the above
The physical layer is responsible for
1.line coding
2.channel coding
3.modulation
4.all of the mentioned
The portion of physical layer that interfaces with the media access control sublayer is called
1.physical signalling sublayer
2.physical data sublayer
3.physical address sublayer
4.none of the mentioned
The _______ is the physical path over which a message travels.
1.Signal
2.Protocol
3.Medium
4.All of the above
Unipolar, bipolar, and polar encoding are types of _______ encoding.
1.line
2.block
3.NRZ
4.Manchester
What is the bandwidth of a signal that ranges from 1 MHz to 4 MHz?
1.4 MHz
2.1 KHz
3.3 MHz
4.None of the above
When propagation speed is multiplied by propagation time, we get the ________.
1.throughput
2.wavelength of the signal
3.distortion factor
4.distance a signal or bit has traveled
which of the following devices is used to connect different network segments and manage the traffic between them?
1.Bridge
2.Hub
3.Gateway
4.Repeater
Which of the following devices takes data sent from one network device and forwards it to all devices on the network regardless of the intended recipient?
1.DNS Server
2.Switch
3.Hub
4.Gateway
Which of the following devices takes data sent from one network device and forwards it to the destination node based on MAC address?
1.Hub
2.Switch
3.Gateway
4.Modem
__ is a type of transmission impairment in which an outside source such as crosstalk corrupts a signal.
1.Attenuation
2.Distortion
3.Noise
4.Decibel
__ 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.
1.Attenuation
2.Distortion
3.Noise
4.Decibel
___ describes the position of the waveform relative to time 0.
1.Frequency
2.Phase
3.Amplitude
4.Voltage
______ can impair a signal.
1.Attenuation
2.Distortion
3.Noise
4.All of the above
_______ data are continuous and take continuous values.
1.analog
2.digital
3.(a) or (b)
4.None of the above
_______ data have discrete states and take discrete values.
1.Analog
2.Digital
3.(a) or (b)
4.None of the above
_______ encoding has a transition at the middle of each bit.
1.RZ
2.Manchester
3.Differential Manchester
4.All of the above
_______ is a type of transmission impairment in which the signal loses strength due to the resistance of the transmission medium.
1. Attenuation
2.Distortion
3.Noise
4.Decibel
_______ signals can have only a limited number of values.
1.Analog
2.Digital
3.(a) or (b)
4.None of the above
_______is the rate of change with respect to time.
1.Amplitude
2.Time
3.Frequency
4.Voltage