A note on cyclic almost difference families

Almost difference families (ADFs) were introduced by Ding and Yin as an useful generalization of almost difference sets (ADSs), and a number of infinite classes of almost difference families had been constructed. In this note, we improve the results of the existence of cyclic (q,6,λ,t)(q,6,λ,t)-ADFs and establish three results of the existence of cyclic (q,7,λ,t)(q,7,λ,t)-ADFs.