Browse Prior Art Database

Simplified Check Character Syndrome Encoders

IP.com Disclosure Number: IPCOM000084763D
Original Publication Date: 1976-Jan-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 3 page(s) / 42K

Publishing Venue

IBM

Related People

Marshall, JW: AUTHOR

Abstract

Block codes in the Galois Fields (2/B/) provide for an arbitrary number of check characters for each set of data signals to be error detected/ corrected. Encoders usually include a shift register mechanism for each of the characters, plus half-adders (modulo 2 summing circuits) and multiply matrices generally denoted by the alphabetic character T. The summers, shift registers, and matrices are interconnected in accordance with a selected algorithm for generating check characters or syndromes.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 53% of the total text.

Page 1 of 3

Simplified Check Character Syndrome Encoders

Block codes in the Galois Fields (2/B/) provide for an arbitrary number of check characters for each set of data signals to be error detected/ corrected. Encoders usually include a shift register mechanism for each of the characters, plus half-adders (modulo 2 summing circuits) and multiply matrices generally denoted by the alphabetic character T. The summers, shift registers, and matrices are interconnected in accordance with a selected algorithm for generating check characters or syndromes.

A multiply matrix can be eliminated by selective interconnections between the half-adders and the multiply matrices. For a two-redundant code, a single multiply matrix T/3/ (a multiply matrix realizing field element T/3/) is eliminated by the illustrated interconnections. HA1 half-adder receives the output of character- 2 shift register and half-adds the intermediate results of C2, if the character-2 register with the input data supplies the result through a single multiply (modulo 2 multiply) matrix T to the character-1 shift register and to half-adder HA2. HA2 combines the partial sum from HA1 with the output of character-1 shift register and supplies the result to the character-2 shift register.

Connection from HA1 to HA2 is a feed-forward connection, as a substitution for the omitted multiply matrix T/3/ (see dotted line circle). This connection can also be considered as a direct feedback connection from the output of the character-2 shift register through HA1 and HA2 to the input of the character-2 shift register.

The broad principles of interconnecting half-adders and multiply matrices can be extended to any number of check character generations. As an example of this extension, a six-redundant code e...