My question may sound a bit strange but i'm trying find out anything about the d,k-codes. I've been give a kind of home task to learn what is d,k-code and how it works. The problem is I can't find anything about such kind of code. After some investigations I asked my lecturer again about the task and got the same answer: find out what are d,k-codes and how they work(he's a bit strange). Now I'm not sure that they exist at, so can you you please help me to understand what this codes are?