Wednesday, 23 January 2013
Q. 1. Telephone Companies use a hierarchy of Digital Signals Service (DS) which have different levels as DS-0, DS-1, DS-2, DS-3 and DS-4. All these levels have different data rates
and are implemented through different types of T lines (from T-1 to T-4) or E lines (from E-1 to E-4) on the basis of data rate in each level.
Now you are required to fill the columns of the given table according to
following instructions:
- Calculate the corresponding data rate
against each number of given voice channels.
- Write the best suitable type of line
(form T-1 to T-4 or from E-1 to E-4 line) with total number of T or E
lines corresponding to calculated data rate. [15 Marks]
Note: Type of line (form T-1 to T-4 or from E-1 to E-4 line) and total number
of T or E lines must be selected on the basis of calculated data rate having minimum wastage of
capacity of the line. Only
optimal solution is required for these columns.
|
No. of Voice Channels
|
Data Rate in Mbps
|
Type of T/E line used
|
Total No. of T/E lines
|
|
50
|
|
|
|
|
90
|
|
|
|
|
140
|
|
|
|
|
195
|
|
|
|
|
600
|
|
|
|
Q. 2. Using Modulo-2 Division and Polynomial x4
+ x3 + x + 1, perform the complete process of Cyclic Redundancy
Check (CRC) on the given message by writing all steps for both sender and
receiver end.
Assume that the message has been received by the receiver
without any error. [15 Marks]
Message:
1010111001100010
