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 ) -ADFs and establish three results of the existence of cyclic ( q , 7 , λ , t ) -ADFs.