CN - ERROR CORRECTION & DETECTION

Techniques for error detection is / are:

• Simple Parity check

• Two-dimensional Parity check

• Checksum

• Cyclic redundancy check

• all options

  Types of error / errors:   

• Single bit error  

• Multiple bits error

• Burst error   

• all options

Error-correcting method / methods used in computer networks………

• Forward error correction

• Backward error correction

• Both

• None

______ is added to the block if it contains odd number of 1’s, and

________ is added if it contains even number of 1’s

• 0, 0

• 0, 1

• 1, 0

• 1, 1

If check sum 11011010 &   complement 00000000 or result is zero then received data is __________

• Discarded

• retransmitted

• interrupted

• accepted

     checksum scheme is based on __________, CRC is based on________.

• Addition, binary division  

• binary division, Addition  

• subtraction, binary division  

• binary division , subtraction

   

Two bits are same (0+0 or 1+1), the result is ____________. Two bits are different (0+1 or 1+0), the result is ________

• 0, 0

• 0, 1

• 1, 0

• 1, 1

In block coding, our message is divided into blocks, each of 105 bits,  We add  25 redundant bits to each block then length n = _________. The resulting n-bit blocks are called ________.

• 130, data words  

• 105, code words   

• 130, code words

• 105, data words

The Hamming distance d(10101, 11110) is _________

• 2

• 3

• 4

• 5

Two-dimensional parity-check can  detect up to  __________bit errors.

• 1

• 2

• 3

• 4