Almost-perfect quadriphase sequences

A new class of quadriphase sequences of length N=p/sup J/+1/spl equiv/2 mod 4(p odd prime, J=1,2,...) is presented. These almost-perfect sequences have a periodic autocorrelation function /spl Theta/ (/spl tau/) which vanishes for all /spl tau//spl ne/0mod (N/2).