Assignment 1:
Aims
- To investigate error correction in digital transmissions.
- To explore voice communication over Internet.
Instructions
Part 1 Error Detection using Hamming Code
Hamming codes ensures that each parity bit is calculated from a distinct set of data bit. As a result, Hamming code can be used for both error detection and error correction.
You task in this part is to identify a single error based on even parity check Hamming Code:
Step 1: write your hamming code number of your group leader's student ID (exclude S): e.g.,
Table 1 student number example
Step 2: represent the odd numbers as "1", even numbers as "0". Table 2 convert digit into binary
|
1
|
0
|
1
|
1
|
0
|
0
|
1
|
|
D7
|
D6
|
D5
|
D4
|
D3
|
D2
|
D1
|
Step 3: Hamming Code calculation. Your task starts now. Good Luck!
Represent your student number into a 7-bit binary follow the instruction in step 1 and step 2;
Create the even parity Hamming Code based on your personalized bit (the data corresponding to your student no.) D7, D6, ..., D1. Then calculate the parity bits r4, r3, r2, and r1, then fill in Table 3.
Table 3 Your personalized Hamming Code
|
D7
|
D6
|
D5
|
r4
|
D4
|
D3
|
D2
|
r3
|
D1
|
r2
|
r1
|
Step 4: Error Correction
Suppose the code word that was received has error in the position of D7, (the opposite binary, e.g., D7 is "1" in your Table 3, then code in bit D7 received is "0" in error, vice versa), other bits are correct.
Then which bit has error at the receiver side?
Part 2 Explore Voice Communication over Internet Protocol (VoIP) (15 marks)
Suppose that Alice is calling Bob using the service of VoIP. You are allocated to explore one of the category VoIP communications from the following a), b), c), and d) based on the last digit of your group leader student number:
a) Telephone to telephone (ending with 1, 2)
b) Telephone to computer (ending with 3, 4, 5)
c) Computer to telephone (ending with 6, 7, 8)
d) Computer to computer (ending with 9, 0)
Your task is to write an essay (within two pages) to address:
- What device involved from transferring Alice's voice to the sound of Bob receives.
- Explain the functions of devices used for data and signal transform, i.e. how the analog voice is converted to the digital or analog signals.
- Draw a diagram to show the information flow and demonstrate in which parts signal are analog, and in which parts are digital. You can use the building block of the following:
You may start to search the key words "Voice over IP" from Google