Ternary (-1,0,+1) almost-perfect and odd-perfect autocorrelation sequences are applied in many communication, radar and sonar systems, where signals with good periodic autocorrelation are required. New families of almost-perfect ternary (APT) sequences of length N = (p n  - 1)/r, where r is an integer, and odd-perfect ternary (OPT) sequences of length N/2, derived from the decomposition of m-sequences of length p - 1 over GF(p), n = km, with p being an odd prime, into an array with T = (p n  - 1)/(p m  - 1) rows and p m  - 1 columns, are presented. In particular, new APT sequences of length 4(p - 1)/(p m  - 1), (p m  + 1) = 2 mod 4, and OPT sequences of length 2(p n  - 1)/(p m  - 1) with peak factor close to 1 when p becomes large, are constructed. New perfect 4-phase and 8-phase sequences with some zeroes can be derived from these OPT sequences. The obtained APT sequences of length 4(p m  + 1), p > 3 and m - any even positive integer, possess length uniqueness in comparison with known almost-perfect binary sequences.
['Evgeny I. Krengel']
Almost-perfect and odd-perfect ternary sequences