A Construction for Periodic ZCZ Sequences
  We introduce a construction for periodic zero correlation zone (ZCZ) sequences over roots of unity. The sequences share similarities to the perfect periodic sequence constructions of Liu, Frank, and Milewski. The sequences have two non-zero off-peak autocorrelation values which asymptotically approach $\pm 2 \pi$, so the sequences are asymptotically perfect. 
Samuel T. Blake, Andrew Z. Tirkel
cs.IT math.IT