Detecting AC vs. DC coupling would be obvious to a practicing EE, if presented with the problem, yes? I&#x27;m just a software guy with an electronics hobby and I think I could have figured that one out.<p>That said, DC vs. AC coupling detection could probably be granted a patent if nobody had &quot;disclosed&quot; the idea prior to filing of such a patent, based on my experience with software patents.<p>Sorry to vent, but patents on this sort of thing drive me crazy. I don&#x27;t have any gripe with you or your post.