Exhaustive search for optimal-PSL quad-phase codes

The task of determining the optimal, as in lowest achievable, PSL for quad-phase codes of a given length involves higher computational effort than for binary codes. Currently the optimal PSL is known only to lengths in the mid-20s. In this paper, we conduct exhaustive search to determine the optimal PSL for quad-phase codes of lengths 25 to 33. For each of these lengths, we also determine the total number of optimal-PSL codes, and the number of optimal-PSL equivalence classes.