Fast and Efficient Three Level Totally Self-Checking Checkers for M-out-of-(2M+-1) Codes

摘要

This paper is concerned with the design of fast totally self-checking checkers for m-out-of-(2m+-1) codes. The new method uses three-levels of gates only and is based on the partitioning of the input lines into m blocks of two lines per block except the last block. A first level of two-input AND and OR gates realizes the majority functions T(k/sub i/greater than or equal to 1) and T(k/sub i/greater than or equal to 2). These are combined through AND gates of a second level into the so-called product functions P/sub j sub 1 j sub 2 ...j/sub m// one for each class of input codewords that have j sub 1 ,j sub 2 ,...j/sub m/ 1's in the corresponding blocks of the input lines. Finally, two OR gates (third level) partition the product functions into two. The property of totally self-checking operation is achieved through the proper partitioning of the product functions into two classes. The paper presents a systematic method of such partitioning. Also the paper determines the cost of these checkers and compares them with previous designs. 5 refs., 2 figs., 2 tabs.