Question

FDD is a simulated method of full duplex.

True

False

A decrease in the minimum required SNR represents improved data transmission capability.

True

False

Signal rate is limited by the channel's bandwidth and minimum required signal to noise ratio.

True

False

Repeaters cannot remove sampling error, also known as quantization error, from digitized signals.

True

False

Digitization introduces quantization errors that cannot be removed by amplifiers.

True

False

Delay spread of optical pulses results on multimode fiber because of multiple signal pathways of different lengths within the fiber.

True

False

The Data Link Layer of the OSI model is the Network Access Layer in the TCP/IP model.

True

False

Services performed at layer one of the Internet model are also found in layer one of the OSI model.

True

False

A +13 dB antenna increases the power by 20 times.

True

False

A radio station broadcasting at 103.3 MHz would transmit radio signals that have a wavelength of 2.90 meters.

True

False

What is the period of the following periodic signal:  y = 3 sin (2π 33,000 t)

		33,000 sec
		11,000 sec
		0.0000303 sec
		0.0000909 sec

What is the wavelength (in meters) of a 5GHz WiFi radio signal, presuming the speed of light is 300,000 km/sec?

		6 meters
		0.06 meters
		16.67 meters
		1,667 meters

What is the maximum amplitude of Y for the following:  Y = 2 sin(2π 2,000 t) + 7.5 sin (2π 2,000 t)   

		2
		-2
		7.5
		-7.5
		9.5
		-9.5

Determine the overhead and throughput for the following system. The system uses frames that begin with one start bit and end with 1 stop bit. The frame also contains five 7-bit ASCII characters and each character has one parity bit following it.

		overhead = 35/40, throughput = 5/40
		overhead = 5/40, throughput = 35/40
		overhead = 0.8333, throughput = 0.1667
		overhead = 0.1667, throughput = 0.8333
		overhead = 94.6%, throughput = 5.4%
		overhead = 5.4%, throughput = 94.6%

You have a cable modem that transfers information at 20.0 Mbps. The bandwidth of the channel is 2,000 kHz. What is the minimum signal to noise ratio that would support this data rate?

		511.0
		9,999,999,999.0
		1023.0
		none of the above.

Determine the value for Z, where Z = 8dBm - 15dBW + 2 dB + 10 dB + 5 dBW

		0 dBm + 5 dBW
		10 dBm
		0.001 dBW
		10 dB
		0 dBm + 10 dBW
		30 dBW

What is the maximum theoretical data capacity on a coax cable that supports 30 MHz of frequency bandwidth and experiences a signal to noise ratio of 10,400 to 1.

		200 Mpbs
		400 Mbps
		800 Mbps
		1600 Mbps

Match the explanations with the appropriate concepts.

A signal impairment that is caused by the overlap of consecutive signals that have spread out in time as they travel over distance.    A signal impairment described as the loss of power of the signal as it travels over a distance. A signal impairment that could be caused by lightning.    A signal impairment that is caused the the transmission of other communication signals that interact with the intended received signal.

A. impulse noise B. interference C. delay distortion D. attenuation

Match the OSI Model layers and with their activities.

Application Layer    Presentation Layer Session Layer Transport Layer    Network Layer    Data Link Layer    Physical Layer

A. Access to the link, follows the rules for access and prepares the final bit stream to hand to the physical layer. B. OSI Model Layer 1. C. Path determination in the network. D. OSI Model Layer 7. E. Formats data so application layer can understand it. F. Manages simultaneous communications processes. G. Handles reliability and end-to-end connectivity.

Select the responses below that are true in relation to the graphic linked below.

Time Domain Graph (in seconds)

	A.	The frequency ( f ) is 3.5 cycles per 2000 micro seconds.
	B.	The period ( T ) is 0.000571 seconds
	C.	The amplitude is 60.

Select each of the below responses that are correct in regard to the linked graphic of a B3ZS line code.

Line Code Graphic

		The graphic shows a signal that will produce the following final binary value: 110011110000001
		This is a bipolar line code.
		The + and - code for the signal is + - 0 0 + - + - + 0 + - 0 - +.
		This code is identified as B3ZS, but the pattern would also be possible in a B6ZS code.
		There are no violations in this code.
		This code is identified as B3ZS, but the pattern would also be possible in an HDB3 code

Select all of the responses below that are correct regarding 7-bit ASCII (table shown below).

7-bit ASCII Table

		The binary code for gOuhL! would be: 1100111 1001111 1110101 1101000 1001100 0100001
		The binary value for the character S will need a 0 appended when using even parity.
		With one start bit, one parity bit and one stop bit, a single 7-bit ASCII character can be sent within 10 bit times.
		The 1111000 character is incorrectly displayed in the table.

A microwave data link has been designed to operate at 110,000 symbols per second while encoding 14 bits per symbol. The receiving equipment requires at least a 50 dB signal to noise ratio in order to operate without significant error.

		At least 55 kHz of bandwidth on the transmission channel are required for the attempted system.
		The data rate of the designed link will be 1.54 Mbps.
		If the actual signal to noise ratio is 100 dB, the system could support encoding as many as 17 bits per symbol.
		There is not enough information given to determine the minimum transmission power needed to make sure an acceptable power level arrives at the receiver.
		Exactly 16,348 different symbols would be needed to support 17 bits per symbol.
		If the background noise at the receiver is -50 dBm, the receive power will need to be at least 1 dBm.

Select all of the responses that are true regarding the below graphic.

Frequency Domain Graph

		The image shows a frequency domain graph with two component signals.
		The second component of the signal has the equation y = 12 sin (2 π 10,000 t).
		The overall equation for the signal is: y = 12 sin (2 π 10,000 t) + 18 sin (2 π 15,000 t) + 8 sin (2 π 30,000 t).
		The equation for the lowest frequency component could be:   y = 8 sin (2 π 10,000 t) + 4 sin (2 π 10,000 t).

Answer 1

Question: The Data Link Layer of the OSI model is the Network Access Layer in the TCP/IP model.
Answer: True
The Network Access layer of the TCP/IP model is equivalent to the Data Link and Physical layers combined, of the OSI reference model. The Network Access layer defines the hardware and protocols that are required for connecting a host to a physical network and for delivering data across it. The network layer is the lowest layer of the TCP/IP model. It defines how data is to sent physically through the network.

Question: Services performed at layer one of the Internet model are also found in layer one of the OSI model.
Answer: True
The Network Access layer of the TCP/IP model is equivalent to the Data Link (Layer 2) and Physical layers (Layer 1) both combined, in the OSI reference model.
Here, the layer one of the OSI model is the Physical layer, and the layer one of the Internet or the TCP/IP model is the Network Access Layer (Layer 1). Same as the Physical layer in the OSI model, the Network Access Layer in the Internet model handles the network interface, the physical media, or cable, it handles and processes data in bits and finally into signals through the physical cables. Both these layers handle protocols such as RS 232, UTP cables such as CAT 5, 6, DSL, Optic fiber.

Question: Match the OSI Model layers and their activities.
Answer:
Application Layer: (D) OSI Model Layer 7.
Presentation Layer: (E) Formats data so the application layer can understand it.
Session Layer: (F) Manages simultaneous communications processes.
Transport Layer: (G) Handles reliability and end-to-end connectivity.
Network Layer: (C) Path determination in the network.
Data Link Layer: (A) Access to the link, follows the rules for access and prepares the final bitstream to hand to the physical layer.
Physical Layer: (B) OSI Model Layer 1.

* The presentation layer changes data into such a form the application accepts. It formats data. It is responsible for the conversion of data formats between applications and networks.
The transport layer provides end-to-end communications with reliable service on an end-to-end basis across the network. It makes sure a complete and reliable delivery of data packets.

* Session Layer manages the establishing and teardown of the association between two communicating nodes. It thus manages communications between connected sessions.

* Network Layer: (C) Path determination in the network: The path determination function enables a router functioning at the Network layer for evaluating the available paths to a destination and for establishing the preferred handling of a packet.

* Division of stream of bits is carried out by the Data Link Layer to hand them to the below Layer 1 Physical layer.

Application Layer: (D) OSI Model Layer 7: It is the top=most layer of the OSI model.
Presentation Layer: It is Layer 6.
Session Layer: It is layer 5.
Transport Layer: It is layer 4.
Network Layer: It is layer 3.
Data Link Layer: It is layer 2.
Physical Layer: (B) OSI Model Layer 1: It is the bottom-most layer of the OSI model.

Question: Match the explanations with the appropriate concepts.
Answer:
A signal impairment that is caused by the overlap of consecutive signals that have spread out in time as they travel over a distance.: (C) delay distortion
A signal impairment described as the loss of power of the signal as it travels over a distance.: (D) attenuation
A signal impairment that could be caused by lightning.: (A) impulse noise
A signal impairment that is caused by the transmission of other communication signals that interact with the intended received signal.: (B) interference

* Delay distortion causes timing jitter problems where the receiver clock deviates from the incoming signal randomly so an incoming signal might arrive late or earlier.
* Attenuation is the signal impairment that occurs by the strength of signals degrading with distance over a transmission link, cable, or media.

* Interference: In general, noise is an error, unwanted or undesired random disturbance in a piece of useful information or an electrical signal. In actual, it is a "crosstalk" phenomenon, which is a source of coupled noise, in which a signal that is transmitted in one channel or circuit of a transmission system creates undesired interference onto a signal in another circuit or channel.

* Whereas impulse noises are spikes or irregular pulses of short duration that are generated by phenomena such as lightning or spark due to any loose contact in electric circuits, etc. Impulse noise produces burst errors and they are the main source of bit-errors in digital data communication. Impulse noise could be unwanted, almost instantaneous sharp sounds produced by scratches on disks, gunfire, electromagnetic interference, explosions, and synchronization issues in digital audio.