Problems a. For multipoint configuration, only one device at a time can transmit. Why? h. There are two methods of enforcing the rule that only one device can transmit. In the centralized method, one station is in control and can either transmit or allow a specified other station to transmit. In the decentralized method, the stations jointly cooperate in taking turns. What do you see as the advantages and disad- vantages of the two methods? 2 The period of a signal is 10 ms. What is its frequency in megahertz? 33. A sine wave is shifted left by a 1/8 cycle at time 0. a. Express its phase shift in degrees b. Express its phase shift in radians 34. Sound may be modeled as sinusoidal functions. Compare the relative frequency and wavelength of musical notes. Use 330 m/s as the speed of sound and the following frequencies for the musical scale. Note Frequency 264 297 330352 396 440495 528 If the solid curve in Figure 3.17 represents sin(2Tt), what does the dotted curve r sent? That is, the dotted curve can be written in the form A sin(2,ft + ); A" f, and d? Decompose the signal (1 + 0.1 cos 51) cos 10 rintoa linear combination of sinusoidal functions, and find the amplitude, frequency, and phase of each com Use the identity for cos a cos b. epre- 3" ponent. Hint: 3.7. Find the wavelength of a 600-THz green light ray in air. Consider two periodic functions f(o) and f(0, with periods T and 72. respectively. Is it always the case that the function ft) fi(t) + 2() is periodic? If so, demonstrate this fact. If not, under what conditions is ft) periodic? 2.0 1.0 -2.0 0.5 Figure 3.17 Figure for Problem 3.5