x = 1

Consider a composite signal with initial power 50W and has the following three components: - Amplitude: 10V, Frequency: 3 Hz, Phase: 0 degree - Amplitude: 3V, Frequency: 9 Hz, Phase: 45 degrees Amplitude: IV, Frequency: (20+x) Hz, Phase: 90 degrees where x is the 3rd digit of your student ID number. (a) Plot the composite signal in frequency domain graph. (6%) (7%) (b) Plot the composite signal in time domain graph for 1 second. Hint: A sine wave can be represented as y(t) = A sin(2nft +0). (c) If the signal travels through a medium with attenuation -2dB, what is the signal power at the receiver? (6%) (d) Suppose the signal lasts for 30 seconds and is digitized by PCM using 256 levels. What is the minimum size of the resulted digital data? (6%)