1. a. A 16 KHz baseband channel is used by a digital transmission system. Suppose ideal pulses are sent at the Nyquist rate, and the pulses can take 128 levels. There is no noise in the system. What is the bit rate of this system? Justify your answer. b. Suppose that multi-level square pulses are used in a digital transmission system, and the maximum pulse amplitude is 1.1 Volt. Suppose that the amplitude of the additive noise is uniformly distributed between ( 0.1, + 0.3) Volts. What is the maximum number of levels of pulses this transmission system can use before the noise may start introducing errors? Justify your answer. c. What is the maximum reliable bit rate possible over a noisy AWGN (Additive White Gaussian Noise) communication channel with 15 KHz bandwidth and 20 dB SNR? Justify your answer. d. Suppose we wish to transmit at a bit rate of 120 Kbps reliably over a noisy AWGN communication channel which has a bandwidth of 10 KHz. What is the minimum SNR (Signal to Noise Ratio) (in dB) required to accomplish this? Justify your answer.