Problem 2 A 1.5-Mbps digital signal is to be sent over an ideal passband radio channel with a 220 kHz bandwidth. The modulation choice is M-QAM with raised-cosine pulses. (a) Find the minimum value of M that should be used to achieve this goal, if the raised-cosine pulses have a roll-off factor of r = 0.35. (b) Once successfully put in operation, the system designed in (a) is subject to bit rate demands that exceed the original 1.5 Mbps. Suppose that you are considering reducing the roll-off factor of the raised cosine pulses to r = 0.21. Find the new bit rate that this link would be able to accommodate if this measure were implemented. (c) What would be the "price" paid by implementing the measure suggested in (b)? HINT: See problem 2(d), HA10).

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