Block coding takes message data and divides it into blocks of k bits called data words. It then adds r redundant bits to each block, making the block length n=k+r bits, called a code word. There are 2^k possible data words but 2^n possible code words since n is larger than k, allowing some code words to be invalid or illegal and ensure the same data word is always encoded as the same code word.

1. Block coding

2. BLOCK CODING
 In block coding, we divide the message into blocks,
each of k bits, called data words
 We add r redundant bits to each block to make the
length.
 n=k+r
 The resulting n-bit blocks are called code words.

3. Block coding
 •With kbits, wecan createacombination of2k datawords; with nbits,wecan createacombination of2”codewords.
 •Sincen>k,thenumberofpossible codewordsislargerthan thenumberofpossible datawords. Thesame dataword isalways
encodedasthesame codeword.Othercodewords areinvalid orillegal.

4. For eg:
If K=4
n=5
2 =2⁴ =16;
2 = 2⁵ =32; (2 – 2 )
16 only valid out of these 32 codewords.
Remaining bits are invalid.
K
n n K

5. Error detection in block coding

6. Thank you