On 5/16/21 09:15, Nico Palermo wrote: > Hi Phil, > > I don't know what Joe used in WSPR but, for instance, he told me that > he generated the sync sequence used in Q65 by means of direct optimization > of its autocorrelation function, not in an algebraic way, so that its > lateral peaks > were minimum only in a limited time shift interval. > I guess that he did something similar also with WSPR.
Thanks Nico. That would actually make sense. Designing sync sequences seems to be a real art form because it depends on just what you're trying to optimize; you can't have it all at once. I have an entire book on the subject. The title is "Radar Principles" by Levanon, but the more you learn about radar the more you realize that radar is essentially the correlation/synchronization problem. I asked because the various writeups mention a "pseudo random synchronization word having good auto-correlation properties" and this usually implies a simple linear feedback shift register or a combination of them (e.g., Gold codes). On the other hand, 162 is not a power of 2 minus 1 so it would have to be truncated from a longer sequence. Phil _______________________________________________ wsjt-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/wsjt-devel
