A randomly generated data stream consists of equiprobable binary

A randomly generated data stream consists of equiprobable binary symbols 0 and 1. It is encoded into a polar nonreturn-to-zero waveform with each binary symbol being defined as follows:
(a) Sketch the waveform so generated, assuming that the data stream is 00101110.
(b) Derive an expression for the power spectral density of this signal, and sketch it.
(c) Compare the power spectral density of this random waveform with that defined in part (b) of Problem.3.11.