ABSTRACT
In many of the previous chapters of this book we have been concerned with the need to be able to distinguish messages from random noise. We have also spent time looking at assessing the information content of messages and the information capacity of channels. One important topic, however, we have taken for granted. Up until now we have assumed that we can easily tell one message from another. We have also tended to take for granted that the chosen patterns or symbols in use can be easily distinguished from one another.
