Standards/BCH
(Difference between revisions)
(Created page with "{{public}} {{TOC right}} [https://en.wikipedia.org/wiki/BCH_code BCH codes] have been invented by Bose, Chaudhuri and Hocquenghem. They are used in communication systems for ...") |
(→Coder) |
||
| Line 21: | Line 21: | ||
The parity bits are created with the help of a [https://en.wikipedia.org/wiki/Linear-feedback_shift_register Linear Feedback Shift Register] (LFSR). | The parity bits are created with the help of a [https://en.wikipedia.org/wiki/Linear-feedback_shift_register Linear Feedback Shift Register] (LFSR). | ||
| + | |||
| + | The following picture shows a BCH encoder with 7 code bits : | ||
| + | |||
| + | [[File:BCH encoder schematic.svg|center|BCH encoder (63, 56)]] | ||
| + | |||
| + | = Decoder = | ||
| + | |||
| + | [[Category:Standards]] [[Category:Codes]] | ||
Revision as of 16:11, 21 July 2016
|
BCH codes have been invented by Bose, Chaudhuri and Hocquenghem. They are used in communication systems for error correction. Similarly to Hamming codes, they are able to detect a certain number of errors and to correct a smaller quantity of them.
These codes are often implemented in addition to convolutional codes.
Definitions
A BCH code is specified by:
-
n: total code length -
k: information data length -
m: parity bits number -
G: the generator polynomial
The coded BCH data is often filled with '0' bits up to a length which is a multiple of 8, thus allowing to be transmitted as bytes.
Coder
The parity bits are created with the help of a Linear Feedback Shift Register (LFSR).
The following picture shows a BCH encoder with 7 code bits :
