We consider q-ary block codes with exactly two distances: d and d + 1. Several constructions of such codes are given. In the linear case, we show that all codes can be obtained by a simple modification of linear equidistant codes. Upper bounds for the maximum cardinality of such codes are derived. Tables of lower and upper bounds for small q and n are presented.

中文翻译：

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关于具有两个距离d和d + 1的q元代码

我们考虑恰好有两个距离的q -ary分组码：d和d + 1。在线性情况下，我们表明可以通过简单修改线性等距代码来获得所有代码。得出此类代码的最大基数的上限。列出了较小的q和n的上下限表。