Hierarchical analysis of high frequency interconnect networks

able to map each input noncode word to an output noncode word, and thus, the SCD property of the whole checker is not lost. Examples illustrating the points a, b, and c have been given in another report [171. V. CONCLUSIONS The paper discusses some important aspects of self-checking checkers and highlights some problems concerning the necessity of the fault secure property for SCD checkers. Some authors have claimed that in order to ensure the exercising of the final checker in a complex self-checking system, the partial self-testing checkers need the fault secure property and some other authors claimed that if the partial checkers are SCD, the SFS property is needed as well. Clearly the fault secure property is not useful for self-testing checkers. For 191 I. E. Smith and G. Metze, " Strongly fault secure logic networks, " IEEE Trans. Comput., June 1978. [IO] N. K. Jha, " Fault detection in CVS parity trees: Application to SSC CVS parity and two-rail checkers, " in Proc. Error securelpropagating concept and its application to the design of strongly fault secure processor, " IEEE Trans. A strongly fault-secure and strongly code-disjoint realization of combinational circuits, " in Proc. 19th Int. Symp. SCD checkers this urouertv is not useful for the exercising of the 1161 E. Fuiiwara and K. Matsuoka, " A totally self-checking generalized. .-of the data, ing is ensured by the technique given in the Section 4.1, a self-exercising checker [14], [I51 is used as final double-rail spaces and verifying the self-checking properties in complex self-824-834, Nov. 1992.. there is a complete or a partial data dependency but the exercis-The SFS property may he useful in case the exercising of the final checker is established by simulation of the whole self-checking system under the fault free condition. In some cases this technique can be used successfully. But in several other cases this simulation can be too complex indeed unpractical even for the SCD/SFS checkers. It is also possible that the system does never generate a vector set which exercises the final checker and of course the simulation cannot ensure the final checker exercising (it just can be used to check if this exercising is ensured). Then, the exercising of the final checker must be ensured by one of the previously proposed techniques and the SFS property of the partial checkers is not useful. The conclusion is that the basic property for …