Single- and Double-Output Embedded Checker Architectures for Systematic Unordered Codes∗

For the detection of all unidirectional errors, Berger codes have been found to be an optimal choice in the general case. But for some particular cases other systematic unordered codes are superior to Berger codes. We present checker architectures for Berger-type codes that are similar to Berger codes. They cover codes by Parhami so that the proposed checkers can also be used for these codes. We also describe new checker architectures for Bose AUED codes and Biswas-Sengupta AUED codes. The design of these checkers is based on translating the code words to words of a Berger-type code which are then checked by a Berger-type code checker. The translation circuits are very simple. All checkers can be tested with only a few code words, or achieve the self-testing property almost independent of the provided set of code words, and are therefore very suitable as embedded checkers. The proposed checkers can be designed to have a single periodic output or a two-rail encoded output. Further, our checkers are not code-disjoint in the common sense but able to detect all single and multiple unidirectional errors.