Hamming Code
What it is and how it works
Information on Hamming code
- It is a character coding scheme
- It checks for binary errors
- Created by Richard Hamming
- Uses parity system to spot errors
- Errors include 0 changing to 1 and 1 changing to 0
- It self corrects errors
- Parities are on bits which are a power of 2
- These include: 1,2,4,8,16
- Pattern is used to see how many blanks there are
- The pattern is n-1
ASCII W 1010111
Bit Position 11 10 9 8 7 6 5 4 3 2 1
Data or Parity? D D D P4 D D D P3 D P2 P1
Data 1 0 1 0 1 1 1
P1 1 1 0 1 1 0
P2 1 0 0 1 1 1
P3 0 1 1 0
P4 1 0 1 0
Code with parity bits 1 0 1 0 0 1 1 0 1 1 0
Correct
ASCII & 0100110
Bit Position 11 10 9 8 7 6 5 4 3 2 1
Data or Parity? D D D P4 D D D P3 D P2 P1
Data 0 1 0 0 1 1 0
P1 0 0 0 1 0 1
P2 0 1 0 1 0 0
P3 0 1 1 0
P4 0 1 0 1
Code with parity bits 0 1 0 1 0 1 1 0 0 0 1
Well done
Bit Position 11 10 9 8 7 6 5 4 3 2 1
Data or Parity? D D D P4 D D D P3 D P2 P1
Data 1 1 1 1 0 1 1 1 1 1 1
P1 1 1 0 1 1 1
P2 1 1 0 1 1 1
P3 0 1 1 1
P4 1 1 1 1
Correct data 1 1 1 1 1 1 1 1 1 1 1
Original data 1 1 1 1 1 1 1
Well done