Error detection and Correction codes:
Parity bit:
A parity bit is used for the purpose of detecting erroprs during transmission of binary information.
A parity bit is an extra bit included with a binary message to make the number of 1s either odd or even.
The message imcluding the parity bit is transmitted and then checker at the receiving end for errors.
An errors is detected in the checker.
|
3-bit message |
Odd parity |
Even parity |
||||
|
A |
B |
C |
Bit |
Parity |
Bit |
Parity |
|
0 |
0 |
0 |
000 |
1 |
000 |
0 |
|
0 |
0 |
1 |
001 |
0 |
001 |
1 |
|
0 |
1 |
0 |
010 |
0 |
010 |
1 |
|
0 |
1 |
1 |
011 |
1 |
011 |
0 |
|
1 |
0 |
0 |
100 |
0 |
100 |
1 |
|
1 |
0 |
1 |
101 |
1 |
101 |
0 |
|
1 |
1 |
0 |
110 |
1 |
110 |
0 |
|
1 |
1 |
1 |
111 |
0 |
111 |
1 |
Hamming Code:
Hamming code not only provides the detection of a bit error, but also identifier which bit is in error so that can be corrected.
Thus, Hamming code is called error detecting and correcting code.
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