Page 85 - Fundamentals of Communications Systems

Signals and Systems Review 2.37

2.7.1 Project 1
Project Goals: In designing a communication system, bandwidth efficiency
is often a top priority. In analog communications one way to get bandwidth
efficiency is to limit the bandwidth of the message signal. The big engineering
trade-off is how narrow to make the bandwidth of the message signal. If the
bandwidth is made too narrow, the message will be distorted. If the bandwidth
is made too wide, spectrum will be wasted. This project examines this trade-off
for a realistic signal.
Get the Matlab file sigsex2.m from the class web page along with the com-
puter generated voice signal. Use this file to make an estimate how small the
bandwidth of a voice signal can be and still enable high-fidelity communications.
There is no single or right answer to the problem but engineering judgment
must be used. How would your answer be different if you were only concerned
with word recognition or if you wanted to maintain speaker recognition as well.
Please detail your reasons for your solution. Relate your results to the different
notions of bandwidth that were discussed in the text.

2.7.2 Project 2
Project Goals: The computation of a percent energy bandwith, B P , requires
a numerical integration to be performed for most signals that are used in com-
munications. This project will assign you to do this integration for a realistic
signal.
Get the computer-generated voice signal from the class web page. Write a
program to estimate the the 90% bandwidth of this signal.