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

What is scan, What is "Scan"? Scan Insertion and ATPG helps test ASICs ...

What is "Scan"? Scan Insertion and ATPG helps test ASICs (e.g. chips) during manufacture. If you know what JTAG boundary scan is, then Scan is the similar idea except that it i

A switch statement , Which is more efficient, a switch statement or an if e...

Which is more efficient, a switch statement or an if else chain? Ans) The differences, if any, are likely to be small. The switch statement was designed to be efficiently impl

What is visibility give uml notation, What is visibility give UML notation?...

What is visibility give UML notation? Visibility refers to the ability of a process to reference a feature from another class and has possible valued of public, private, protec

Engineering phyics, what is interference of light explain the nessicity of ...

what is interference of light explain the nessicity of coharent source for obtaining sustain interference pattern

Explain scientific applications and image processing, Scientific Applicatio...

Scientific Applications/Image processing Major of concurrent processing applications from science and other academic disciplines, are mostly have based on numerical simulations

Develop an object-oriented design, Investigate the MIPS programmers model a...

Investigate the MIPS programmers model and develop an object-oriented design that will reflect aspects of the MIPS architecture. Consider the functional units of the architecture a

System software, define the properties of interactive operating systems

define the properties of interactive operating systems

Design a half adder, Q. Design a half adder? In half adder inputs are: ...

Q. Design a half adder? In half adder inputs are: The augend let's say 'x' and addend 'y' bits. The outputs are sum 'S' and carry 'C' bits. Logical relationship betwee

Determine the block diagram of bcd adder, Determine the block diagram of bc...

Determine the block diagram of bcd adder To add 0110 to binary sum, we use a second 4-bit binary adder. The two decimal digits, together with input-carry, are first added in to

Selecting integerated learning experiences, Q. Selecting integerated learni...

Q. Selecting integerated learning experiences? It is important that we select appropriate experiences for children, more so those that are from the child's world and emerge fro

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