Over the weekend I received a number of e-mails asking me general questions about xMax and XG Technology. I want to make it clear once again that I have absolutely no interest in discussing this company, its business prospects, or anything related. My interest in xMax was only on the technical side. At this point it is very clear that xMax is a modulation technique which uses unconventional waveforms. It offers nothing new from the standpoint of communication theory. The fact that it is possible to use many types of waveforms for communications is very well understood. It is also well understood that the performance of systems using any kind of waveforms must be close to that of systems with conventional waveforms. This fact and the Shannon theorem clearly indicate that the performance claims made about xMax are false. I really don’t know what else to say on the technical side – this is such a clear cut case. If and when new experimental data becomes available I will be glad to comment. Also, if anyone has specific technical questions I will be glad to address them. However, I am really not interested in expanding the xMax discussion beyond the technical issues, and do not intend to post responses to non-technical questions about this technology, so please do not send these to me.
The real issues underlying the xMax story are not technical. They have to do with some fundamental conceptual error or misunderstanding by the developers of xMax, which has some similarity to the conceptual errors of the proponents of VMSK. This would be clear to any competent communication engineer who takes the time to read carefully the Bobier patents and some of his published statements. Someone with a good understanding of communications theory would not and could not make the kind of performance claims which have been made about xMax. If the gentle reader has any doubts about my assessment I can only suggest that they look for independent verification from several experienced communication engineers. If the reader is connected to XG Technology I suggest that they ask the company to show them the xMax BER vs. Eb/N0 curve which I have discussed in previous posts (I would appreciate if you let me know what happened …). There is really nothing I can do, or want to do, to change anyone’s mind. For further insight into persistent delusions I refer the reader to the classic 1952 book “Fads and Fallacies in the Name of Science” by Martin Gardner. Gardner’s book is somewhat out of date and has no examples of wireless fallacies, but there are some important lessons that can be learned from it.