Pseudorandom Arrays for Built-In Tests

Parallel pseudorandom sequences for use in built-in test are discussed. The two-dimensional nature of these sequences-makes it natural to consider the resulting binary arrays. Some of the desired properties of such arrays are discussed, as well as some of the problems. Generators for such arrays are described. A conventional LFSR with parallel output is shown to be a poor choice for such a generator. Several compact generators are described, which are shown to be compromises between complexity and varying degrees of implementation of the desired properties in the resulting sequences. One of the compact generators produces sequences which have the desired properties for built-in tests.