Read Chapter 4 in your text and Lesson 4.  Then complete this homework. Work to understand all problems even though all problems may not be assigned.

1. List the advantages and disadvantages of different cable types in the table below.

	Advantages	Disadvantages
Twisted Pair
Coax
Fiber

2. Use figure 4.1 in your text and answer the following questions.

a) What range of wavelengths does AM radio use?

b) What range of frequencies does AM radio use?

c) Which has the largest bandwidth according to the figure, twisted pair, terrestrial and satellite, or infrared transmissions [be careful]?

3. Look at figure 4.3 in your text and answer the following questions.

a) What frequency offers the lowest attenuation per kilometer for optical fiber [be careful]?

b) If the total permissible attenuation is -40dB, how far could our cable stretch without a repeater for:

twisted pair?
coax?
fiber?

4. Describe the difference between a repeater and an amplifier.

5. Why are repeaters superior to amplifiers?

6. What are the differences between single-mode and multi-mode fiber, and which one, in your opinion, is technically superior?

7. For a satellite transmission system:

a) What would the attenuation be for be for a signal traveling from a satellite to an earth station if the distance is 25,000 kilometers and the frequency of the signal is 2.45 GHz? Give your answer in dB.

Attenuation for a radio link to space can be estimated with the following equation:

L = 10 log [ (4 pi D / lambda)² ]

lambda is the wavelength
D is the distance
L is the attenuation in dB

b) What would the received signal power be if the satellite transmits at 40 dBW?  [please note that we switched over to working in dB]

c) Would the received signal power in 'b' be sufficient to meet a signal to noise ratio of 30 dB if the noise level was 10^-8 W ?

8. What is the maximum theoretical capacity, C, on fiber if the available bandwidth is 18 THz and the signal to noise ratio is 40 dB?

9. Explain the need for catagory 6 and catagory 7 cabling.

10. Why are wire pairs twisted?

Used with permission of the Author; Copyright (C) Kevin A. Shaffer 1998 - 2018, all rights reserved.