Download Characteristics of the Physical Layer Signals and Propagation

Homework
Chapter 3: Physical Layer Propagation
Characteristics of the Physical Layer Signals and Propagation
1.
a) What is a signal?
b) What is propagation?
c) What are propagation effects?
d) Why are propagation effects bad?
Binary Data Representation
2.
3.
a) If you have N bits, how many things can you represent?
b) If you have 6 bits, how many possibilities can you represent?
c) If you have four bits, how many possibilities can you represent?
d) If you need to represent 40 courses offered in a department, how many bits will you
need per entry?
a) How many bits does ASCII use to represent keyboard characters?
b) If you transmit “Hello World!” (without the quotation marks) in ASCII, how many
bytes must you transmit?
Multistate Digital Signaling
4.
a) Distinguish between the bit rate and the baud rate.
c) If you have 10,000 clock cycles per second, what is the baud rate?
d) If you have 10,000 clock cycles per second and you transmit in binary, what is the bit
rate?
e) If instead you have 10,000 clock cycles per second and use 16 voltage levels for digital
signaling, what is the bit rate?
f) To transmit 30 kbps over a 10 kbaud line, how many possible states will you need?
Unshielded Twisted Pair (UTP) Copper Wiring
5.
b) What is a length of UTP wiring called?
c) In 4-pair UTP, how many wires are there in a cord?
c) How many wire pairs are there in a cord?
d) How are the two wires of each pair arranged?
Attenuation and Noise Problems
6.
a) Describe the attenuation problem
b) Describe the noise problem.
b) What is the limit on UTP cord length in Ethernet standards?
Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall
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Optical Fiber
7.
a) What is the main benefit of optical fiber compared with UTP today?
b) Which costs less to buy and install—UTP or optical fiber?
Optical Fiber Construction and Operation
8
a) In optical fiber, what are the roles of the core and the cladding?
b) What are the two most common fiber connector types?
Radio Signal PropagationFrequencies
9.
a) Distinguish between omnidirectional and dish antennas in terms of operation.
b) Under what circumstances would you use an omnidirectional antenna?
c) Under what circumstances would you use a dish antenna?
Network Topologies
22.
a) What is a network topology?
b) At what layer do we find topologies?
c) List the major network topologies, Present each topology in a separate paragraph.
Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall
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