Explain about hamming error correcting code, Computer Engineering

Assignment Help:

Q. Explain about Hamming error correcting code?

Richard Hamming at Bell Laboratories worked out this code. We will only introduce this code with help of an illustration for 4 bit data. Let's presume a 4 bit number b4, b3, b2, b1.  In order to create a simple error detection code which detects error in one bit only we can just add an odd parity bit.  Though if we want to find which bit is in error then we may have to employ parity bits for different combinations of these 4 bits in such a way that a bit error can be recognized uniquely.  For illustration we can create four parity sets as below

Source Parity                            Destination Parity

b1, b2, b3                                                        P1                                            D1

b2, b3, b4                                                        P2                                            D2

b3, b4, b1                                                        P3                                            D3

b1, b2, b3, b4                                                  P4                                            D4

Now very interesting phenomenon can be noticed in above displayed parity pairs.  Assume data bit b1 is in error on transmission then it will cause alteration in destination parity D1, D3, D4.

ERROR IN                                                     Cause change in Destination Parity 

(One bit only)

b1                                                                                             D1, D3, D4

b2                                                                                             D1, D2, D4

b3                                                                                             D1, D2, D3, D4

b4                                                                                             D2, D3, D4

Figure: The error detection parity code mismatch

So by simply comparing parity bits of source and destination we can recognize that which of four bits is in error. This bit then can be complemented to eliminate error. Please note that even source parity bit can be in error on transmission but under assumption that just one bit (irrespective of data or parity) is in error it would be detected as just one destination parity would be different. What should be length of error detection code that detects error in one bit? Before responding this question we have to look in comparison logic of error detection. Error detection is done by comparing two ‘i’ bit error detection and correction codes fed to comparison logic bit by bit (see figure below). Let’s have comparison logic that produces a zero if compared bits are same or else it generates a one. Consequently if similar Position bits are similar then we obtained zero at that bit Position however if they are dissimilar that is this bit position may point to an error then this Particular bit position would be marked as one. This way a matching word is built. This matching word is ‘i’ bit long so can signify 2i values or combinations.


Related Discussions:- Explain about hamming error correcting code

Describe about frameset, Q. Describe about Frameset? Now make a master ...

Q. Describe about Frameset? Now make a master page in which you write below code. My Frame Page -- The Master Page

Explain about interlacing, Q. Explain about Interlacing? Interlacing is...

Q. Explain about Interlacing? Interlacing is a procedure in which in place of scanning the image one-line-at-a-time it's scanned alternatelyit implies thatalternate lines are s

Define the operand data types, Operand is that part of an instruction which...

Operand is that part of an instruction which specifies the address of source or result or the data itself on which the processor is to operate. Operand types typically give operand

I have a user defined function that does not recalculate, Contain all the c...

Contain all the cells that your UDF depends on in the argument list. Or enter this as the first statement in your Function: Application.Volatile This will cause the functi

Explain anonymous FTP, Explain Anonymous FTP. Use of a login password...

Explain Anonymous FTP. Use of a login password and name helps maintain file secure from unauthorized access. Though, sometimes these authorizations can also be inconvenient.

What is artificial intelligence language processing, Artificial intelligenc...

Artificial intelligence language processing (AILP) is a field of computer science and linguistics concerned with the interactions among computers and human (natural) languages; it

Explain hypertext transfer protocol, Explain Hypertext Transfer Protocol. ...

Explain Hypertext Transfer Protocol. HTTP is used mainly in today's society like a set of rules for exchanging files (graphic images, text, sound, other multimedia files or vid

Appropriate problems for ann learning, Appropriate Problems for ANN learnin...

Appropriate Problems for ANN learning: Conversely as we did for decision trees there it's important to know where ANNs are the right representation scheme for such job. Howeve

What is gustafsons law, Q. What is Gustafsons Law? Amdahl's law is app...

Q. What is Gustafsons Law? Amdahl's law is appropriate for applications where response time is significant. On the other hand there are numerous applications that necessitate

Character and string processing instructions, Character and String Processi...

Character and String Processing Instructions: String manipulation usually is done in memory. Possible instructions comprise COMPARE STRING, COMPARE CHARACTER, MOVE STRING and MOVE

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd