Efficient exhaustive search for optimal-peak-sidelobe binary codes

An efficient exhaustive search routine is given which finds all binary codes of a given length having autocorrelation PSL under a given size. It was applied to two tasks, the first of which was to find all optimal-PSL binary codes of length 64. 1859 were found, of which 142 are balance-equivalent, i.e., they can be transformed to a balanced code by a combination of three PSL preservers. The second task was to find a PSL-4 binary code for each code length from 61 to 70, to establish 4 as the optimal PSL for those lengths.