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NET 222: COMMUNICATIONS AND
NETWORKS FUNDAMENTALS
(PRACTICAL PART)
Networks and
Communication
Department
Tutorial 4: Chapter 5
Data & computer communications
Chapter 5 pages 176-177 (Data & computer
communications)
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Problems:
 5.1
 5.6
 5.7
 5.9
 5.11
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Question
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5.1 Which of the signals of Table 5.2 use
differential encoding?
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Answer
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NRZI, Differential Manchester.
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Question
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5.6 For the bit stream 01001110, sketch the
waveforms for each of the codes of Table 5.2.
Assume that the signal level for the preceding bit
for NRZI was high; the most recent preceding 1
bit (AMI) has a negative voltage;
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Answer
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Question
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5.7 The waveform of Figure 5.25 belongs to a
Manchester encoded binary data stream.
Determine the beginning and end of bit periods
(i.e., extract clock information) and give the data
sequence.
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Answer
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Networks and Communication Department
Question
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5.9 The bipolar-AMI waveform representing the
binary sequence 0100101011 is transmitted over
a noisy channel. The received waveform is
shown in Figure 5.26; it contains a single error.
Locate the position of this error and explain your
answer.
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Answer
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The error is at bit position 7, where there is a
negative pulse. For AMI, positive and negative
pulses are used alternately for binary 1. The
pulse in position 1 represents the third binary 1 in
the data stream and should have a positive
value.
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Question
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5.11 Given the bit pattern 01100, encode this
data using ASK, BFSK, and BPSK.
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Answer
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The End
Any Questions ?
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