CS601 Data Communication Assignment 3 Solution Fall 2012

. 1. Calculate the baud rate against given bit rates by following the methods of given modulation techniques against each bit rate. Write all necessary steps, formulas and units. Also write any 2 possible constellation points of given modulation techniques by considering their given configuration changes (amplitude, phase).                                                                                                                        [ 15 Marks ]


a)      4000 bps                                                          16-QAM

b)      25000bps                                                         32-QAM

c)      48000bps                                                        64-QAM


Modulation         Bits/Baud                 Baud rate    Bit rate

16-QAM                      4                              N                 4N

32-QAM                      5                              N                  5N

64-QAM                      6                               N                  6N

Q. 2. You are required to make a comparison between Single Mode and Multi Mode Fiber Optics on the basis of given parameters.                                                                                                                [ 5 Marks ]


Single Mode


Size  High `100 Terahertz  150/300 MHz-km
Distance  Single Mode fibers are used for high speed data transmission over long distances.  They are able to carry more data than single mode fibers though they are best for shorter distances because of their higher attenuation levels.
Light Source
Attenuation  Resistance  0.35 / 0.25 dB/km They are less susceptible to attenuation than multimode fibers.  3/1 dB/km  higher attenuation levels.
Cost  Expensive  Less Expensive