1. CEG3185 : Introduction to Computer Networks SEG3155 : Communication and Networking
Tutorial 4

2. Q1: Coding Techniques
Assume a data stream id made of ten 0s. Encode this stream using the following encoding schemes. How many changes (vertical line) can you find for each scheme?
Unipolar
Polar NRZ-L
Polar NRZ-I
Bipolar AMI
Pseudoternary
Manchester
Differential Manchester
B8ZS
HDB3

3. Q2: Modulation and data rate
Calculate the bit rate for the given baud rate and type of modulation:
1000 baud, FSK
1000 baud, ASK
1000 baud, 8-PSK
1000 baud, 16-QAM

4. Q3: Pulse code modulation (PCM)
Data from an analogue source ranges in value between –1.0 to 1.0 volts. Assume a uniform quantification of 8 bits. What binary values (you may express the values in decimal) correspond to the following source values?
0.91 volts
-0.25 volts
0.5 volts
0.495 volts

5. Q4: Quantizing Noise
Consider the transmission of a voice analog signal (spectrum between 500 Hz and Hz) with a digital signal using PCM.
Assuming samples are quantized using an 8-bit code, what is the minimum data rate required to transmit the voice signal?
Given M=2 (2 levels in the digital signal), use Nyquists formula to determine the medium bandwith necessary to support the transmission of the signal.
Determine the level of quantizing noise (decibel).