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One major change is the elimination of the ineffective chapter summaries. Instead,<br>new Online Activity sections have been added to give students the opportunity to<br>further explore new communications techniques, to dig deeper into the theory, and to<br>become more adept at using the Internet to i nd needed information. These activities<br>show students the massive stores of communications information they can tap for free<br>at any time.
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ECE 3125 ~ ECE 3242 Due: Nov 26, 2012 Assignment 2 1. Obtain the power spectral density of a stationary binary random process with auto- correlation function 1 – (│τ│/ T ) τ≤ T Rx(τ) = { 0 τ≥ T 2. Explain, with the help of appropriate examples and diagrams, the following (a) Modulation in communication systems (b) Difference between analog modulation and digital modulation (c) Baseband modulation and passband modulation (d) Line Coding (e) Line coding operations viewed as examples of Digital Baseband Modulation. (f) Nyquist’s Sampling Theorem (g) Nyquist’s Transmission Theorem 3. (a) Assuming that binary data bits 1 and 0 occur with equal probability, calculate the average normalized energy spectral density of binary PAM waveforms representing two data bits using rectangular pulses of amplitude A and duration T (NRZ-L Line Coding). (b) Repeat the calculations for Manchester line coding. 4. (a) Obtain and sketch the sequence of individual sinc-shaped pulses at the output of minimum bandwidth Nyquist filter corresponding to the input data sequence “1101001”. (b) Use the results of 4(a) to obtain and sketch the overall resultant signal at the output of minimum bandwidth Nyquist filter corresponding to the input data sequence “1101001”. 5. (a) Demonstrate duo-binary encoding and decoding operations for the following sequence {xk} = 1 0 0 1 1 0 1 0 1. Assume the first bit of the sequence to be the startup bit (not part of the data). (b) Demonstrate duo-binary encoding and decoding operations with pre-coding for the sequence as in 5(a).