记环R=F_p~k+uF_p~k+u~2F_p~k,定义了一个从R~n到F_p~k~(2np~k)的Gray映射.利用Gray映射的性质,研究了环R上任意长循环码.证明了环R上任意长码是循环码当且仅当它的Gray象是F_p~k上的准循环码.特别的,环R上的线性循环码的Gray象是F_p~k上的线性准循环码.
Let R = F_p~k + uF_p~k + u~2F_p~k,a Gray map from R~n to F_(p~k)~(2np~k) is defined.Base on the property of Gray map,cyclic codes of arbitrary length over R are studied.It is proved that a code of arbitrary length over R is a cyclic code if and only if its Gray image is a quasi-cyclic code over F_p~k.In particular,the Gray image of a linear cyclic code over R is a linear quasicyclic code over F_p~k.