On line-of-sight microwave systems, 5, 6, 7, and 8 bits per hertz of bandwidth are fairly common. SIGNALS CONVEY INTELLIGENCE Chapter 9 provides a more detailed discussion of radio systems. REVIEW EXERCISES 1. Name at least four different ways of communicating at a distance prior to the advent of electrical communication. 2. What kind of energy is stored in a battery? 3. How did the old electric telegraph communicate intelligence? 4. What limited the distance we could transmit with electrical telegraph before using a repeater? Give at least two ways we could extend the distance. 5. How could that old-time electrical telegraph operate with just one wire? 6. Name at least four ways we might characterize a "sine wave" either partially or wholly. 7. What is the equivalent wavelength (2) of 850 MHz; of 7 GHz? 8. What angle (in degrees) is equivalent to 3/2? to /4? Give two examples of baseband transmission. Define modulation. 11. What are the three generic forms of modulation? What popular device we find in the home utilizes all three types of modulation simultaneously. The answer needs a modifier in front of the word. Differentiate an analog signal from a digital signal. 13. Give at least four applications of a 1-bit code. We suggest using imagination. 14. What is the total capacity of a 9-bit binary code? The Hollerith code was a 12-bit code. What was its total capacity? 15. Name four different transmission media. What is the opposite of loss? What is the most common unit of measurement to express the amount of loss? What is the reason of twists in twisted pair? 18. What is the principal cause of data rate limitation on wire pair. What is the principal drawback of using coaxial cable for long-distance transmission? 20. What is the principal, unbeatable advantage of fiber-optic cable? 21. Regarding limitation of bit rate and length, a fiber-optic cable may be either 22. Explain dispersion (with fiber-optic cable). 23. What are some typical services of LMDS? REFERENCES 1. From Semaphore to Satellite, The International